. Most airlines go there, You should get a good connection anywhere.
And You also have the busiest apt of Germany as a playground...
As You obviously plan a trip to Sinsheim - don't miss the museum's branch in Speyer! AN22, Dassault Mercure, and the by now famous 742...it's about half an hour away from Sinsheim, actually a bit closer to FRA
...to reach the famous spotter's platform near rwy18 You might want to have a car or a cab, it's a bit to walk...so try to find "sixti", it's a LCC-type of rental cars, You will get a Smart for 5€ a day, Focus Wagon for 8€ (weekends cost a bit more)...just in case money does matter...if not, You can rent a SL500...
would be longer driving, probably about an hour, maybe a bit more, also is the less interesting apt compared to FRA
Baden-Baden could be an alternative if You're coming in on FR
, but there are hardly any flights, so maybe difficult to get a connection, but it's for sure closer than Hahn, FR
's Germany hub #1....