Were looking at Mission Texas for the winter. All new area to us, by what I see on the web we like What Benston Grove Resort has to offer. They have a ton of activities. Figuring 2 months Feb and March just to get our feet wet. Any opinions on the area or resort? Happy trails.

We've done a number of "mission" trips (no pun intended) in the area of Weslaco (not too far away).

Areas are hit and miss. The border issues seem to have subsided the last we heard from our friends who still live in the area. You will see a lot of Border Patrol and Highway Patrol. There are checkpoints from time to time. Take off your hat and glasses if you pull into one.

This map will show you the current crime rates. Where you are considering seems to be pretty safe.

https://www.neighborhoodscout.com/tx/mission/crime

You will only be about an hour or so from Harlingen, Texas. This is a pretty modern town. Lots to do there. We've spent some time at the beaches of South Padre Island. The water is a lot cleaner than up by the Houston area.

And, if you need a roadside grocery stand, there are a lot of them in the area of the border crossings. Some really good ones are in the Progresso area. They are kind of scattered around, but many are cheap. They were loaded in the early spring and throughout summer. Not sure about winter but worth the check:

The place you have picked out seemed a little high for the area. But after looking at the amenities, it might be worth a few more dollars if you enjoy those things (I mean that in a good way). There are number of other less-than-resorts that run $300 to $350 a month. They are more stripped down but still nice. And they are gated.

If you pick this spot out for sure, let us all know what you think when you get there.

If you cross the border, the parking can get a little tight. There is not much parking at this crossing.

This is Progresso (Mexico). Take your passport...

Weather should be pretty nice. But when it rains, things get real muddy...And, it can flood. Be watching. The entire area is pretty flat. Water will pile up as it really has no where to go. We got caught with a hurricane to our backside as we pulled out. Later, most of that area had 2' or more of water on the ground. That's an hour inland. You won't experience hurricanes at that time of the year. But a thunderstorm is not out of the question.

https://www.usclimatedata.com/climate/mcallen/texas/united-states/ustx0854

We toured that area back in 2010. Maybe we were a bit early (December) but South Padre Island was cool and a bit breezy and the stickers were bad. The mission area was a bit busy for us (But that's maybe just us).
You may want to go on RV.net and look at the snowbirds forum, the admin there stays at Benston Palms I believe. He may want to give you his opinion. There are lots of posts and opinions there.

We have been in the area many times. We have decided against South Texas because of the wind. We have been discussing where we will spend months at a time in the winter and have many options in AZ. This year we are heading for the FL gulf coast area before we make our final decision in the winter of 2018.

I agree with Ron about the Rio Grande valley area, too windy. We grew up in the Texas panhandle & had enough wind to last a lifetime. Other than the wind it's a nice winter area.
As for Florida the temperatures are near perfect for the winter, but for us the humidity/dampness was a killer on our arthritis, toooo many bugs, & too moldy smelling. We tried central Florida, east coast & the gulf coast & it was all about the same. Also the prices are higher than Arizona or Texas.
We've now chosen central Arizona about halfway between Phoenix & Tucson, this will be our 4th season in this area & really like it. So much so we bought a small house in Picacho Peak Rv resort, the park may be a bit remote for some, but in 30 minutes in either direction can purchase anything we need.
There are so many great snowbird areas all across the country & I hope you are able to try them all. Go enjoy the experience!