Your problem seems to be mostly related to the fact that you have a (full coverage bolt on) fender, and do not know how to properly set your chain tension by hand.

It shouldn't take you any longer to take your wheel off than that of a geared bike. The only thing slowing you down is your fender (and maybe a few seconds from un-doing the axel bolts).

Also, it's safe to ditch the chain tensioner, worthless gimicks.


EDIT: everything peabody said too.