Go with Murs Radios
Hi there.
I few tidbits from my personal experience hunting in hilly terrain with radios. I'll list a few points of interest.
1. Range can be much greater with VHF than UHF (ie, MURS goes further than FRS/GMRS), even at the same power level.
2. An antenna 20 feet up or less should easily hear all the handhelds (vhf/MURS) in your lease from a central location (even w/a very mediocre antenna).
You describe your lease as 200 plus acres. Assuming a perfect square, I see that the maximum length (in reality I realize this is probably not the case), two people could be from each other is about 7 miles. You will have trouble finding any handhelds that will reliably talk this far away, though they may work sometimes.
So practically speaking, even though with vhf handhelds, many of the ppl in a 200 acre space could reach each other most of the time, it will be far less than 100%. With UHF(FRS/GMRS), you can forget about it, being anywhere near reliable over that kind of distance (even though it may work perfectly in spots).
So what to do?
The VHF/MURS Route from a system standpoint:
Get a bunch of these radios on ebay, brands like quangsheng, jintong, but I like Puxing. Set up one radio with external antenna a few feet up. Most handhelds will reach each other most of the time, but they should always be able to talk back and forth with a base. (VHF/MURS does not allow repeaters, although it may be legal to use a simplex repeater, I'm not sure). A simplex repeater needs only one radio channel, the repeater (a higher antenna base station), simply listens and restransmits anything heard on the same frequency.
For GMRS, you'd need a license, and have the expense of setting up a full fledged (duplex) repeater about 30 feet up or so at the camp. Handhelds would be limited in their ability to go direct to each other, but should always be able to talk to each other through the repeater.
Bottom line, given 200+acres, and typical realworld conditions without perfectly flat terrain, reliable handheld to handheld coverage is difficult to achieve with VHF, and very unlikely with UHF. But the use of the base stations or repeaters described before can bridge this gap.