My wife and I (early 30’s – two young kids) have set our sights on the Mt. Helix area in recent months for the same reasons you’ve been looking; bigger lots, more house, CHARACTER!!!!
We rent in a master planned community now (Escala in Mission Valley) and I can’t wait to get into a real ‘neighborhood’, which I feel La Mesa/Mt. Helix really is. The new communities are nice, but I want some charm and a parcel bigger than a postage stamp. I’ve found some nice fixers on Mt. Helix, but the prices have been pretty sticky as you noted. I’m waiting as I feel prices will continue to fall for at least another 6-9 mos.