The workouts up the alpe are good if you can do it in 60-90 minutes. I use the keyboard to skip ahead so that I finish the workout near the top and then I either ride down for a cooldown and get easy 250xp, or I just let the avatar coast down while I wrap up my ride. I made a custom workout that was all 55 or 62 second interval blocks and was getting close 12xp a minute doing that, doesn’t matter what wattage they are, you can even do long zone 1 or zone 2 workouts up the alpe if you make a custom one. I once took over 2 hours doing that and it was boring but it’s a good XP haul, and if you need drops you’ll make a lot doing this, plus you get a chance at the lightweight wheels, which afterward if you land on that you get a 1000xp bonus.
Another good way is to ride with coco cadence, usually I end up 38-40km/h doing that so 740-800 xp an hour for that. If Paris is the guest world you can hop on a TT bike and do laps there, it’s 2 banners every lap so +20xp and 140 regular xp. It’s better than a workout if you can average 33km/h I think. You can also manually navigate a loop through the Italian Villas in Watopia now and hit that sprint banner ever ~2km so another great spot to do laps. I haven’t done a full hour yet to see how much XP that one gets but if you don’t need to get elevation for the everest challenge the TT bike is a good way to go, especially if workouts aren’t your thing.