Stop in for a cup of coffee

Soooo I've got yet another crazy *** idea.

A cruise when my dart is done from my house to St. Louis(via us 50). to LA via Route 66(or as much of it as is left), then a cruise up Pacific Coast Highway to Seattle, then US Route 2 To Maine and then back to Indiana.

Think it can be done in 4 weeks?
Why only 4 weeks?