Boardwalk is steel but a smaller diameter top tube, and since torsional stiffness is a 4th power function of diameter, it should be a lot less stiff and more noodly when climbing standing. Mariners of the last decade are aluminum frame (some earlier or non-USA ones were steel or had skinny frames like a boardwalk). To keep the frame and (old style) handlepost hinges from creaking, they need to be adjusted really tight, and also a drop of oil on the hinge pin. But my improvised deltech cable has made a huge difference in the frame hinge, tightened that right up, and I haven't needed to adjust the hinge since, three years now. Also, adding a lock nut to the frame hinge adjustment helped too. Used to be adjusted monthly.

As far as riding... regarding ride quality, yeah, not much to do about that. If you mean shifting, my early Speed had both the terrible forward-mounted Dahon rear derailleur, and really terrible cogs with semi-circular impressions that were useless compared to real hyperspaceglide, but it only mattered on the big low cog, where it was dang near impossible to get it onto the cog without adjusting the RD so it frequently overshot the chain into the spokes. But, changing to a conventional derailleur (Shimano Tourney TX 6/7 speed with claw mount as no standard RD mount), resolved that, shifts perfect even with those poor cogs.

With my mods, 2X gearing, deltech, mine climbs darn nice for a folder. Bigger tires should help ride, I've only used 1.5" and 1.75", I'm gonna go to 2.0".