We have a pretty long cord - 50' maybe 100'? I don't know why it's so long but I think it might have something to do with the "hydro" boxes in Canada are sometimes quite a stretch from where you would actually park the camper. Anyway, we have it on a old-fashioned plastic cord wrapper - just un-spool what we need and it fits in the "rabbit hole" no problem. Like this one:
150 ft. 16/3 Extension Cord Wrap-HD-150PDQ - The Home Depot.
One time, we actually stayed in a campsite that had a broken 15 amp socket. Luckily, we were able to borrow a 30A-15A adapter from another camper. I bought one for our kit as soon as we got home! This is the one we have (with light):
https://www.walmart.com/ip/Road-Power-30-15-Amp-RV-Power-Adapter/16817350
Tim keeps a little voltage tester in the galley drawer, just in case the electricity isn't working - usually because I didn't turn on the post switch (did not know that was a thing) or maybe the GFI got tripped. Looks like this:
Klein Tools Non-Contact Voltage Tester-NCVT-1SEN - The Home Depot
He also has one that he can plug into the socket to make sure everything's OK - looks like this:
Klein Tools Receptacle Outlet Tester-RT110 - The Home Depot I think it's more for wiring sockets, but it's got a place in the galley drawer and I know he's used it on occasion.