Traveling through Europe for 39 days with my female friend in May / June. We want to camp to save money. Suggestions for good campgrounds to stay?

Hey everyone, thanks for reading. I've been to Europe a few times but it's been a while since the last time. As far as traveling, I've gotten a little lazier and I'm spending more time in one place. I'm looking to do the complete opposite on this trip now. Me (30F) and my friend (29F) are planning on traveling through Europe, and we were thinking to go through a few different countries, but have no idea yet on the best places to visit. We are American and live in the United States, but we've both lived in Europe before so we know what to expect. We don't plan on doing any sort of island hopping, and we're not going to go to Eastern Europe. The only two places I know I want to visit / stay are in Barcelona and Rome. I'm looking for suggestions to stay in one place for a few days, and not bounce around constantly. We're also looking to drive. I've done a lot of traveling in my life and have been to a lot of places in Europe, so I'm not opposed to visiting a lot of the same places / cities. She has been to Europe once before but it's been a while, so I'm thinking there are a few places I've visited that she would enjoy. We're looking to save money by camping as much as possible. I'm not opposed to staying in a hotel or airbnb if you have a recommendation. Also looking for some good recommendations for campgrounds. We're just looking to have a good, relaxing time in Europe. I'm not picky. I'm looking for recommendations or possible itineraries. I know it's not a quick trip but we're both looking forward to what Europe has to offer. I'm not really opposed to visiting places I've been to previously. TIA!