Bit of a longer reply.
Its a split transition and a PITA if you don’t have a car… but not impossible. It is an easy drive from UK, about 9 hours from Calais. However, fly to Nurenburg and hire a car is a good option.
Roth Hotels will be very expensive on race weekend, however, lots of locals also welcome triathletes. Camping is also a viable option… campsite is at T1. Dormero Hotel is the most convenient in Roth, the run goes right past it, and it is a 10min walk to athletes village.
For hotel one option is to get a room early… the other strategy, that I followed is wait until almost race day and rely on athletes getting injured and pulling out at last minute (worked well for me twice).
You want to be there on Saturday for Practice Swim at 0700. If you can get there early, doing a lap of the bike couse is well worth it so that you can get a feeling for the course, however, not a disaster if you cant get there early.