Reed Richards directs the team to Dr. Doom’s town, saying Doom has the necessary tech to get them back home. This is a bit like a Wizard of Oz story. They get there, and they stumble into a fight between Doom and Puppet Master. Interestingly, this weaves directly into Fantastic Four #246-247, which continues the Doom/Master battle.
Sadly, though, for the ‘nauts, they don’t find any way home and are still stuck on Earth.