I moved out of KPOU a year ago after almost 20 years there. Jim and the guys at Aero Mechanical are good guys and are willing to help out when they can but as you say, they work on certified aircraft. Parts, advice and yes, he will lend hand.
Likewise, the folks at the avionics shop are always willing to help out. Gretchen and her husband (forget his name at the moment) along with a very friendly golden (Snowball?)will take care of you.
But, for general maintenance, you will be largely on your own. Make friends with the locals, there is always help. Vince (Waco) in the hangar next to Aero Mechanical is a good help and knows where to go.
Also, go across the river to Old Orchard, a great grass strip. It is private but they will welcome you. Lots of knowledge there, repeat RV offender Ron Daniels will help out and always has a Klondike bar in his fridge and week old coffee ;-). Southeast corner, fourth (maybe maybe now) hangar from the end.
In any case, tell everyone I said hello, I'll be back this summer at least a couple times for the Thursday cookout at the orchard.
Scott A. Jordan