well, you can't keep the fam blindfolded forever. at some point they will have to experience all the craziness of the world. in my opinion denver is a good place to start because although different than the smaller communities in colorado, its not outrageous. its good for people to be exposed to that stuff once in a while as long as they are taught about it. theyll see worse at college.
the greenpeace and PPH folks are easy enough to avoid. just stay off 16th. after living here a few years ive decided to avoid 16th street on many days, only occasionally going there if there is a particular restaurant i want to go to. it draws more creeps and beggars than the rest of lodo. there are plenty of restaurants, micro brews, interesting shops, etc in the rest of lodo. if i had kids id spend 90% of my day down by the river. ive kayaked it, rafted it, swam with my dog in it, played water games with friends, then check out rei, maybe do some free rock climbing, then hit up a restaurant or cafe in the area (allowing dogs to chill while you eat is always a nice bonus). ive been all around the US and in my opinion denver is the best or next best city ive ever been to. their downtown has lots of options, interesting privately owned shops and eateries, is easily accessible, cheap parking, overall VERY safe, and in many ways beautiful. the river park is kept natural prairie like, the baseball stadium sells $4 tickets for every game, and its actually a quite quiet downtown. most major cities are dirty, ugly, too congested, impossible to park or walk anywhere and very dangerous.
i love this city.