Something to consider is the antenna...
A commercial radio (such as a Motorola) in the MURS (150mhz band) and the GMRS (462~467 band) will also allow you to use an external antenna, and for occasional use a roof mount mobile mag mount antenna will do more for you than trying to pump a few watts through a "rubber ducky" on the radio inside a vehicle...
Depending on distance and terrain, IF you travel in reasonably grouped "packs" along a highway MURS should work just fine...
An advantage to being licensed to use a radio in the GMRS service is that in some locations REACT teams monitor & operate on a GMRS channel (usually 462.675mhz)...
No matter what band, get a roof mount antenna, an external speaker (amplified is preferable) and a speaker mic if the radio Is handheld.
If you want to use a mobile type radio you have more watts available...just make sure you're within the power and frequency limits specified for the radio band you're operating in...which should be set up by a licensed (& competent) radio shop...even with user programmable radios, if you don't know what you're doing it's possible to screw things up...
In some locations there are GMRS repeaters that will increase coverage...some repeaters are "open" & can be used by all persons, others are "closed" and you must have advance permission to use their repeater (just like Ham repeaters)...access is usually facilitated by the PL or DCS tones...
As mentioned by others, IF you intend to use radios more often, you might consider getting a no-code Tech amateur license, although EACH person using a ham radio MUST have a ham license...whereas on GMRS as long as 1 person in a family group has a license all persons in that group may operate a GMRS radio...