...Any insight on CB vs walkie talkies for mobile communications would be great. For all I know, they could be the same thing at this point!..
"WalkieTalkie" is anything small enuff to walk and talk. You can get a walkietalkie for almost any P-2-P radio service. The small ones may like to say "handheld".
"CB" is a radio band(s) set aside for general personal communication. I am reading-through this period in Electronics World; the 1945 original 460MHz(!) band was used somewhat, but late 1950s 27MHz (an old ham band) was allocated to CB, electronics costs came down (it picked-up slumps in the TV market) and then the 1970s; YOWSA! My T-burd had two CB radios (27 from Ford and then 40 channel aftermarket). Took all day to get the AM radio working instead of the CB (they all ran on one whip).
CB is NOT for "skip" or long-range contacts, nor for rag-chewing. In 1963 the FCC was taking guys to court. I suspect the band is now a ghost-town, although the less remote parts of Maine may be the place someone always has ears on. FWIW, the limit on CB power is (was?) 5 Watts, though SSB may use another number. Steven King WKIT has 5,000 Watts (on a slightly higher band) and is weak 30 miles away, so 5W may not be many miles, especially in dense brush and lumpy terrain.
Amateur radio, Hams, have many bands from low to high, and powers up to 1000W (you won't do that on a motorcycle, no matter how many wheels it has, prolly 20W or 100W; 2-5W in a walkietalkie). There is a test. I think the code test is dropped. Knowing code would let you punch-through really bad conditions, and there's probably an app for that.
I was gonna translate the "Greenville {to} Old Orchard Beach" path then remembered who is asking. (For lurkers: it's like 100 miles, on the edge of the 100 Mile Wilderness, to the sea, and a lot of wooded lumps along the way.)