I think that you will find that in a class B motorhome, a toad will not be a requirement. You will probably enjoy the freedom of needing to hitch up before leaving camp too!
I have gotten my 27' class C into many small parking lots, and parking at a grocery store is only a matter of parking further from the crowded area next to the entrance. I would park over one of the lines, taking up about 4 spaces, so that it is easy to get out of the space. Many parking lots are required by the city to have say 200 spaces, but they only have a minimum size of about 7.5' X 16' long, and that is only enough for a small car. They have no incentive to make the spaces larger, and can have more square feet of rentable space for each parking spot they can have on the property, so there is incentive to create more spaces, even if they do not fit modern cars between the lines.
Out sightseeing, there normally are locations for parking motorhomes and tour buses.
Enjoy your travels!
Fred.