Hey there

I'm in Portland also and am 62 years old, 6'5" and 320 lbs. Check out Meticon Bikes on SE Foster about 62nd, City Bikes (two locations on SE Ankeny), Community Cycling Center on NE Alberta at about 19th, Backpedal Refurbished Bikes on SE Harold at 72nd and WTF Bikes on SE 12th and SE Powell (next to Aladdin Theater). I would suggest steel frames, wide-ish tires, and triple chain rings and wide range cassette, possibly older MTB set up for comfort, utility. This will get you riding, not break your bank account and let you build up to the Trek and Beach Cruiser, both physically and fiscally. Or Not.

Warmest regards and enjoy your rides!