1) Since the old town has not moved since the Middle Ages, and is unlikely to do so any time soon, I am confident that any mapping software can provide all of the needed distances.
2) A simple way to see room types that can accommodate your party size is to, in fact, enter that number into the appropriate drop-down box on the Hilton web page, and then search. In this case, it indicates that the Queen rooms have sofa beds, and that the suites can accommodate your party as well.
3) My experience has been that this property participates in Hilton Honors; it certainly did when I was there and I do not expect that to have changed. Any reports to the contrary on TripAdvisor are more likely the result of someone paying a non-qualifying rate and being confused about it.