I'm afraid I won't have the money for a two to three week long road trip for quite some time (I don't fly, so I'd need to drive both directions). Hotels get expensive. Would be nice to build up my accruals a little more at work and pay off my student loans too. At least after my one week long trip to Florida and back next month, I should at least have a better idea of what long trips are like.
I actually do have some idea of what my first planned cross-country trip would look like. I'd head west on I-90 to clinch it, south to Portland (hopefully they won't completely toll I-5 or other roads, but at least that would be merely disappointing), do a loop to the coast to visit "Arcadia Bay" (yeah, I'm a huge fan of Life is Strange), and head back east along I-84 and I-80.
The only other transcontinental routes I currently have plans of clinching are I-95 and the mainline Trans Canada (TCH 1, ON 17/417, A-40/25/20/85, NB 2, NS 104/105, and NL 1, though I also want TCH 1 in PEI). Maybe I-80, I-70, I-75, and I-85 eventually depending on what the future holds.