|PTing with DS#1 was so easy, really. He let us put him on the toilet and was happy to produce, which gradually led to dry/clean diapers and longer spacing between toilet visits until we put him in underwear around 28 months or so, and I can count on one hand the number of accidents he's had since then. We really couldn't turn the entire process over to him until quite a while later, though, as he simply wouldn't tell us he needed to go (or willingly leave his projects). But he was fine with our taking him to the toilet every few hours.
DS#2, however, has been a different story. He finally stopped resisting using the toilet (I was not fighting him, but trying occasionally to gauge receptiveness), and seemed pleased with being able to stay dry. He was even briefly in underwear, but now has regressed to the point that I put him back in diapers with covers (was using diapers without covers for a long time, since he was having just the occasional poop accident). He's again resisting visiting the toilet, which makes it hard to be proactive, and if we can get him there we won't sit there very long, only to poop in his pants five minutes later. It's very frustrating indeed to have been so nearly "there" and now have regressed. He does at least tell us when he's just wet or pooped, so he's clearly aware. It's tempting to go completely back to diapers and just skip the potty attempts, but I feel like that would be too much of a mixed message. We're just trying to be patient and praising the successes, but the interior monologue goes "ARGH! Could you please just use the toilet like I know you can?" We've tried mild rewards, big boy underwear as incentive (he likes them, but almost seems to have more accidents in them). It will come with time, it will come with time, it will come with time . . .
Re. being on the road, though--for some reason DS does not resist using the toilet on the road, and I think part of that is that he loves his little potty that I keep in the trunk. He is very small and hate the toilet-seat adapter (one of those that folds up) that worked very well for his older brother, so I've give up on public toilets for anything but "flying standing-up tinkles" (I hold him up over the toilet, complete with theme song--he usually goes for that) and now just line his little potty (like a babybjorn one) with paper towels, sit him on it, and he'll cheerfully produce. Disposal is a bit of a treat, but hey, easier than on the pants, right? There are lots of neat portable potty products out there (best one I've seen is by Cool Gear, and I'd love it but can't justify the cost when I had a little potty already) and maybe something like that would help when out and about?