FRS is a decent all around (very) short range solution. 1/2 watt. Line of site is good but as mentioned in broken terrain or heavy cover it will not work well. But the radios are plentiful and cheap and small and in wide use. FRS also works perfectly fine for 'vehicle convoy' car to car comms, as long as everybody can see each other. Somebody gets lost or breaks down, they're going to be out of range immediately.
Chief problems are limited power, snubby fixed antennae, but they run on AA batts and for a good while. And require no license to operate (due to their limited power and range). The fancier versions use frequency splitting for 'privacy' channels. The 'privacy' is purely by dint of nobody else being around on that split frequency. FRS has 14 channels, typically.
GMRS has a bit more power and range (2 watt mobiles and there are 5 watt base stations), but also have a fixed antenna (required by type). They have 22 channels, the first 14 being in common with FRS. Many models also have NOAA Weather channel reception. A useful thing when afield. Also run on AA batts. GMRS requires a 'family license' for a moderate fee, to use legally. They are available in all sorts of bubble packs for very reasonable prices. I don't know what the intricacies of the 'family' license are, but you could do so and get a 4 pack of radios for you and yours, and tell everyone else to get some FRS radios. Then at least you are all 'interoperable' and the GMRS could serve as a base station in effect, with it's longer broadcast range. A GMRS at the base camp, A GMRS in the field with the group or pairs of hunters, everybody else with an FRS and that way everybody can stay in reasonable communication, even if it require relaying messages from weaker to stronger devices.
HAM, lots of powerful options, small and big, all requiring study and licensing (at a cheaper price than the GMRS Family license, IIRC). There are a lot of very inexpensive radios available in recent years, source of a lot of friction in the radio world as they are often illicitly used, HAM snobbery etc. The nice thing about them is you can use them to monitor FRS, GMRS, MURS quite readily. But it isn't legal to them to broadcast on those frequencies except in case of a real emergency. To my thinking they might make a great inexpensive monitor radio in a 'base' setup, especially something ad hoc like a search or rescue operation, tornado disaster etc. Worth having just for that alone. I'm still trying to get around to taking my HAM Technician test so I can actually use the thing, but I've got a nice kit bag put together with additional antenna options, battery packs, power converters etc. Just in case it's needed. Already lost one house to a major earthquake. And thinking about moving to tornado country.
All of these radios come in versions small enough to clip thru a lapel button hole or lash to a pack or belt or suspenders. Smaller than a pack of cigarettes, in many cases. And they are very light for what they are. And almost all of them have inexpensive optional 'hands free' ear clip speaker and boom mic setups. A bonus for hunting as well. Very little noise to spook anything.
