All very good points mentioned above. And since my name was mentioned, I'll chime in.
I've got a 2m rig in my heep, IC-v8000 (75w max), and no idea what antenna, but it's a 5/8 wave stainless steel whip, with the L-bracket drilled into the spare tire carrier on the tailgate, drivers side. No picture of that sadly. Set for as close to 0 swr as possible right smack dab in the middle of the 2m band (146.00 mhz). Decent quality coax from our friend at the Road King, and a mounting location (lets see if I can dig up a pic)...
As for the cb antenna, its one of them looong stainless ones from the Road King, same coax, and its mounted to the passenger side of the spare tire carrier. Eventually it'll be run thru better coax, a tuner, and to an IC-7000.
The antenna's serve me well, they are tree, garage door, and parkade resistant. Useful to hang laundry on. And if I can see the tip of the 2m in the rearview mirror, it's really, really windy. I check the NMO connections in the fall, use a dab of vaseline to keep the junk out, and the coax connectors I have siliconed. It's worked sofar, with minimal tweaks in swr.
As for the "can turning up the power reach someone?" Well, my radio, at full jam, can usually (usually) kerchunk the RYC repeater from nearly anywhere. As for getting a proper return, well, that might mean moving the jeep a couple of feet in some direction. Even when doing car rally's back in Powderface trail, there are some really bad shots to the RYC repeater, and full jam, and a bit of positioning finesse with the jeep will usually get a pretty darn good in & out signal.
When in the bush, and a signal needs to get out, get to the top of the nearest hill. Done. The Eastern Slopes are very, very well covered with 2m repeaters, many with autopatches. But in the event of a Pan-Pan, a lot of casual listeners will turn up the volume, and if need be, lend a helping hand getting a call out to Emergency Services. I haven't had to do that yet (knock on wood), and I don't look forward to the day when I do have to do that, but I feel quite confident that I can get a message out. If all else fails, the the SPOT gps thinger, or a sat fone will work. I'm getting me a SPOT thingy for xmas, so, I feel double secure in next years wheeling adventures.
I personally don't have much use for crossbanding, at least not in the heep, maybe in my upcoming Daily-Driven-Non-Jeep. But I'm an Icom guy, so *shrug*. I have a couple of handy's as well, of which, one always has a blown 2m final, I have a bad antenna, don't know which one as I have a few.