Yep.
When you have some results with some specific antenna, please update.
If using external antenna consider mounting it on a pole. Height is might. You’ll then have to pick a coaxial cable with weather resistance. Water loves to travel down inside and outside of cable. Protect the joints and use a drip loop to keep the water out of the project box. This is a new rabbit hole to explore.
Perhaps a much simpler solution would be to use a freezer sensor(433mhz) specifically designed for really cold environments and use an rtl-sdr dongle inside with either an external antenna on roof or inside. I pick up a number of acurite 986 freezer thermometers on 433 that I think belong to a food hall >200m away.
You will find MANY data points/opinions on the Internet, some of them are even true in some cases. I have some experience in this area and some knowledge of the physics involved. What you are asking for (several hundred feet through trees) is incredibly challenging for standard Wi-Fi. You might be able to do it, but it will likely be expensive and/or unreliable. 2.4GHz does not travel through trees. It also has fairly high attenuation in free air.
There are solutions. Wi-Fi Halo is one.
I looked at this part: Wi-Fi HaLow: Long-Range, Low-Power IoT Connectivity with Sub-1GHz Technology
It would also need something for the other end.
The other option is a pair of HaLow devices. One connects to your home network and the other provides a local Wi-Fi network.
HaLow will give you a standard network so OTA will work. Lora is only for communication. You will have to manually update and there is currently no esphome support. Tasmota has some support, but not clear how useful it is yet.
As far as RF goes, it all comes down to how far above the noise is the signal. I have fiber to my barnyard and then Wi-Fi from there. I have had several APs there and some work better than others. I am currently using Unifi AP-LR and have three spread out to just okay coverage of the area. I have two devices that are 40-60 feet away and they are at the edge of okay. This is without any special antennae or modifications. You need 5X or more distance. That will not be easy.
The other option is Lora. I chose this one. Range is no issue for this. Software support is incredibly challenging. It is NOT beginner friendly. If you go this path, you will in the deep end for sure.
As far as range claims go, you generally need to take them with a whole shaker full of salt. Lora has claims of a few to dozens of kilometers. I started having issues at about 150+ meters. I am sure I could do better with some changes, but 150m is more than I need.
So, battery is important, but communications even more so (for your scenario) since it will drive your battery/power needs.
great idea.
There are also ready to buy ones at your favorite online store.
That might take away the “fun” part of it for you, but I suspect you will find plenty of fun things about the rest of the project. It might also be an easier on ramp to this world.
And like usually, there’s an esphome component for that: Remote Receiver — ESPHome
I was going to say that a better title might have garnered more replies. But you received plenty of replies. 
A better title would however still help others in the future who are looking for similar information. 
Adding to above.
While 2.4ghz has low range especially with obstacles on the way, also data rate matters. For example:
EspNow has much better range than Wifi.
Some inexpensive NRF24 modules can reach ~1km with a line of sight .
What if he called it “Baby, it’s cold out there”
@TRS-80 I would be happy to change the title to something more descriptive if I could. Can I? However, so many different topics were covered well that it would be difficult to get a descriptive title. I am open to suggestions (if it can be changed). It is still a research project for me that I hope to start on shortly. But the object of the project is a hobby farm and it is spring time now…
The title is still… Would you click it if you were looking for solution to operate lifepo4 battery powered board at low temperatures?
Anyway, you can update the title after you have finished your setup…
Admittedly that was based on discussions for LiOn and LiPo batteries … but I personally would still feel safer with regulated 3.3v power than relying on the actual devices to line up just right with manufacturers specs.
The actual efficiencies will vary depending on what components are used. The point was to make the OP aware that there is a trade-off for using much more common and otherwise convenient 5V devices.
Wow, that’s a new one for me ! I doubt someone has made an Excel integration … but Libre Office Calc can use files in other formats. I expect it would be much easier for HA to output or append data to a .dbf or .csv formatted file … which could then be read and manipulated by a macro in Libre Office.
… and a quick search does reveal other users with the same goal.
With the right keyword search you will find threads from others who have done this.
… and that is what makes this hobby so enjoyable interesting frustrating
I’m not sure about the current state with ESP32, but when I tried similar with an early model RasPi it required two antennas - one configured for the AP software, and the other configured as the wi-fi client.
Height definitely reduces the amount of obstructions in the way of the signal - but I have seen many warnings that having a long cable between the device and antenna can actually loose more signal strength than you gain … so be aware.
Good expensive cable can make a big difference over 10s of meters runs. A few meters of medium quality/ not break the bank should be OK of antenna on a pole. Its all trial and error as you suggested.
@donburch888 The more I think of it the more I think that some direct way for HA to edit files could be useful. For me, generating a CSV is only marginally more useful than doing nothing. There is still the manual step of loading the CSV. Also, working with a CSV file is very restrictive. Other users might want other applications that don’t support CSV format. The feature should be generic enough to handle almost anything. I will propose this to the HA new features forum and volunteer to build it. I would hope for significant support and supervision since I am a newbie.
More generic than CSV? Libre office calc??
You can’t store media in a CSV. HA would not directly call into Calc or any application. I envision that HA would provide an interface with generic actions that automations (or perhaps other scripts) could then use. The actual detail work would be in the integration. The interface calls might include: under file, new, open, delete. Then there would be under record (or something) find, new, edit, save, delete. Application specific integrations would then be responsible for the implementation details of those actions. Well defined generic interfaces are the only way to go.
I was thinking about this more and realized that the functionality to do this may already exist in HA. I could probably write an integration for an external application that exposed specific properties and actions, just like other integrations. Like I said, I am a newbie and don’t know that much about HA.