OK, FYI , I do exactly as you say at home. Plug in to 15amp outlet in my shop with a pigtail adapter to my tt 30amp cord.
The situation I asked about comes from visiting my daughters home in Jax. Cannot park in front of their house. I have to park across the street. Will have to run a cord across the street ( after a couple of days of use ) to charge the battery. Will do this at night when traffic is less.
I don't have a short twist 30 amp to 15 amp adaptor cord, which I guess would work. Definitely don't want my 30amp 25' cord sitting out, it might walk off. It is a nice neighborhood but i'd rather just risk a charger and ext cord to theft.
Plus I am thinking the battery charger would charge faster than the tt converter. Is that correct?