I've charged at RV parks, and as I recall, we spent maybe an hour (and $10) to plug into an outlet. But that wasn't a 30 amp, but a 14-50 outlet. As to finding hotels with 50-amp outlets, I usually search for "hotels motels with 50-amp outlets." But nowadays, there are so many superchargers it's almost ridiculous to spend time thinking of charging overnight at a motel. I've also found that having a Model S, with 400 miles of range, charging is seldom a worry.
- It's worth an extra $20 to find a hotel with charging, so try that first on plugshare. Some day a site will combine plugshare with a hotel search to let you do hotel search with hotels-with-chargers highlighted in red.
- Yup on the RV parks. Now 30A RV only gains you 100 miles in a night but it's still nice. There are often RV parks with cabins, and you can stay in those and charge, if they have a spare 50a.