The down side to linear amps is they can generate a lot of interference. Enough oomph and your signal can bleed into a lot of stuff.

If there is a setting for taking stills, your battery life is greatly increased. Or video to card and a motion sensor. I had a remote setup using a motorcycle battery, it didn't last long before it was time for a recharge.

I haven't tried a large number of linears, but the ones I have tried seemed to suck a lot of power.

Linears aren't real expensive $30-$130 price range. VHF repeaters can be expensive. Boosters are moderately priced, coax isn't cheap.

The way I see it your biggest issue is the constant feed, you may be spending half your time recharging. A motion activated camera would likely extend battery life.

I really don't know a lot about what you are doing, just throwing some ideas out there.

Only three choices I can see, RF, cellular or cable. I have no idea what a cellular plan would cost for your application. But may be the better option if you have decent signal where you are at?