There also may be a disadvantage in that 'Park Homes' on residential sites are probably lifed - I would guess about 20 years. That is not to say that that they can't stay on a site longer but it is something that you should enquire about. I know that quite a few residential sites have a minimum age limit, say residents must be at least 50. This can be an advantage.
I like the concept myself but they aren't particularly cheap now-a-days are they!
Also, as a thought, if you bought on a site that was a bit remote you may find that in a particularly hard winter you get trapped by your surroundings. So therefore if you are going to live closer to a town, you may be able to find an apartment locally for the same price as a Park Home.