Biking isn't allowed on the boardwalk, but walking your bike on that part is acceptable.
I think it would depend on your bike, skill level and how many times around the loop you want to go. It didn't take my baby wearing friend and me a real long time to get around the loop once on foot. There were some short spots that were steeper and some that were a little rough with tree roots and such. Been a while since we went though.
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