yes to a dolly for the surfboard, i made a rack for my HAD which works pretty well (I even carry my SUP on it) but a dolly would be equally doable and would have the advantage of not adding weight when I'm not going surfing (or, not adding something I need to take off when I'm not surfing). Also the dolly combined with a plank of wood or two might make a serviceable general-purpose trailer for luggage missions!
anyone any thoughts on ride quality between those 2 options? I think there is a bit of conflict between the two - smaller more nimble and slower on the open road, or larger better for the open road but less nimble and takes up more space....
EDIT: interestingly
this very detailed write up says that 20 inch wheels are only very slightly slower than 700 and the difference probably isn't noticeably by the average cyclist on paved roads (on rougher surfaces bigger wheels have more advantages).
"0 Based on my tests in Seattle, while riding over the same paved 25 mile route with my BF (20”x43 mm tires @ 65 psi)) and with my Surly LHT (700Cx38 mm tires @ 70 psi), there is a small increase in rolling resistance. The BF is a fraction slower – perhaps 0.5 mph. This may have been due to the wider tires and lower pressures. On paved roads, I don't think the difference between 700C and 20” tire diameter will matter to the average cyclist. In any event, I have become quite used to the speed of my BF on this tour. After 11,000 LHT touring miles, the LHT is still my favorite bike, and is better than my BF on gravel roads especially if there are rocks or sand. My Troll, with front suspension, is better than both bikes on bad roads."
(he's carrying a lot more stuff than I am likely to be carrying)