First, forget about #3.

Second, it sounds like you've never done anything like this before. Don't back yourself into a corner by trying to sell in a hurry in Nicaragua. Maybe it works out (you should really read up on this) and maybe it takes a while.

Third, riding in Central America is as tame as you want it to be. Don't like "dangerous areas?" Don't go to any--same as if driving through Oakland, East LA, or Brownsville. By the time you get to Nicaragua, you'll probably have figured this out...and if you don't Managua might teach it to you. So my vote goes to #2, except I'd sure leave myself more than a week to get back; you might make it, but you won't be having much fun along the way. Better two weeks, and even then won't do much but ride.

In fact, if that's an example of how this trip has been planned, maybe think again.

You might consider turning back before Nicaragua when the timing tells you it's time to head north. There's nothing special about getting all the way there--it's not as if that's the end of the line. Besides, you'll find Guatemala (or even Mexico) exotic enough to satisfy, and you'll have stories for your envious friends.

Otherwise, maybe leave your bike there, fly home, then fly back and rejoin Dad for his return journey. Most countries allow this, but verify about Nicaragua.

Hope that's helpful.

Mark

PS: Not everyone wants to spend infinite amounts of time with their fathers, pre or post-mortem. With mine, a week was always plenty, two weeks way excessive. YMMV.