We have lived in NorCal and currently live in SoCal. NorCal has a fabulous cycling infrastructure and many areas of interesting and challenging terrain. I would rate it very high against the best cycling in Europe.
Internationally, we have cycled in Italy, France, Switzerland, Greece, Croatia, Tahiti, New Zealand, Mexico and Spain. We have traveled with our bikes including the tandem. Although, it is work to do packing and unpacking as well as transit of the bikes, it is worth it. We did a rental once in Tucson, AZ and it was okay but not great.
Next year, we are making our 4th trip to Mallorca, Spain and we will take our road bikes. Although, Mallorca has many rental bike options. Mallorca is ground zero for cycling and many UCI pro teams have training camps in Mallorca and there are numerous sportivs and other cycling opportunities there. We rent a car large enough to carry luggage and two bike boxes and then use the car to take our bikes to various parts of Mallorca for rides.
We have done two training camps in Tucson, Arizona. Tucson has Mount Lemon which is one of the more challenging climbs featuring 26 miles of climbing. I did it once on a rental bike and another on my road bike. I prefer my own bike. I have zero experience with folding bikes. I find it hard to imagine tackling the terrain around and including Mount Lemon on a folder. But, if one has the juice in the legs, probably not a problem.
The other aspect of Tucson was so so road surface quality and wind. Fast legs and time in the saddle make any riding condition possible and enjoyable.
We have found the road surface conditions are important to have a great time cycling in an area. Tuscany had great roads and picturesque scenery but hard cycling. New Zealand had hard cycling and rougher roads. Greece and Croatia had hard cycling and spotty road surfaces and crazy traffic.
So when one selects a bike to ride for a period of time in a new area, it is good to know the terrain and match the equipment and ones fitness and skill to where one is going to cycle.