You can do without it, but you have to plan for it. Like Tig said, layout the well to house supply line with the slope that will allow you to drain the line and tank. What the valve really helps do is release the vacuum formed by the water column in the well and supply line. Plus, somewhere around your pressure tank there will be a check valve that isn't going allow the water to go backwards. That will complicate your life a bit when trying to drain the supply line. There will be a boiler drain valve installed in the supply line on the well side of that check valve along with the drain down valve in the well. You could put that in either way for $2.99.
If the valve prevented you from having to replace the water line once, it will have paid for itself. To replace the line, it will have to be dug up from the well to house. There goes your landscaping. You can save some of that by running a 4" PVC pipe from your basement wall to the well, putting the supply line inside that pipe. All of this is well below frost line, for you at least 5'. The pressure tank itself is hellishly expensive but easy to drain. Wish I had a better answer on the pros and cons vs money spent.
Dave.
Thanks again for the assist Dave. I had a 2" knock out put in at the center of the rear foundation wall about 1-2 inches off the floor that's well below 5 feet from grade. I planned to put the expansion tank in this general area. My concern is with the pipe freezing in that first five feet south of the where the pipe enters the house.
My guess is that (and it's just a guess) the downward slope you guys mentioned should extend to the entry point in the well casing in order to get the water in the line away from the house regardless of whether there's a drain back valve. Unless of course the valve release is strong enough to suck all the water back down??? Do you know of any issues with these valves failing? I try to hew toward simple in these designs if possible.
I had trouble getting the foundation drain to daylight, running into some kind of shale (sedimentary) ledge along the way. I hope I don't hit the same thing here. And the PVC conduit sounds like a good idea.
All the points you raise about monitoring the place have entered my thoughts at one time or another. I had a draw string installed for a land line and there's WIFI available from a local broadband provider. I haven't decided on what to do yet with that. Until then, the diamonds and furs will be traveling back and forth with us...