Ok, spent a while on my folding bike, first off the seat tube angle is super bad, measures at 70* AND the BB is on the front side of the seat tube so the "actual" is even worse, so I moved the seat WAY forward, now the "actual" seat tube angle is 73*, sweet.
I also replaced the rear brake cable and housing, the shift cable and housing, and put a new shifter on, well, its old, but in very good condition, and I put some new rubber on, rated to 100 PSI, the thing does seem to roll somewhat better with 95 PSI in the rear, but I don't expect too much out of the 16" wheels in that regard. The front brake was actually kinda FUBAR'd but I had parts I robbed from another caliper brake in a parts box to get it tip top, put some kool-stop pads in it too, much better braking now, also new pads in the rear.
I also pulled the 165mm steel cranks off and replaced them with 175mm MTB cranks, the bad seat angle plus the short cranks was a really bad combo, I'm stoked to get both of those sorted! But I needed a longer BB spindle to make that work, and I had several to choose from, I have great chain line now, and I lost nearly a pound off the bike with the crank swap, BUT I will have to pull the drive side pedal when I fold the bike now as the original crank did fold to deal with the pedal, but that crank was also bent slightly so going to the MTB cranks got rid of that slight bend as well :-) I might pick up some folding pedals at some point.
I did go back to a 46 tooth ring and I think that will work well all in all, it's also in notably better shape than the 48 I had on there for yesterday's ride...
I'll get some better pics soon.