What advice would you guys give?
Not advice here but a couple of observations. As in any endeavor, one gets out what one puts in. Building is a huge plus for me (although I do own a couple ARFs, but they are of birds that aren't kitted). Building/tuning are hard-won skills, as I'm sure they are for the boats. I hope there's very little market for RTR in your case, as those types usually have the attention span of a border collie on crack!
I wonder what it is mentally that occurs between age 11 to say 16? Ever notice that things picked up during that time stay throughout ones life? Music, RC, cars, Ham, maybe they all belong under 'eye/hand' skills.
The other related thing is the general dumbing-down of our society, and the scorn displayed to those who are more technically adept. Few schools have a science department, as I had, and in my case the teacher was a Ham operator who was enthusiastic and inspired his students. No answers here, only more questions...