All best wishes your way, Dave; I can relate. There is a reason why I have my Nomad setup with 36x17 gearing...and at times have wished for lower. It is worse if you make the crossing by logging roads, as the grades can be 24%-31% on semi-graded ballast.
The big thing here is you cannot count on anything being open. Entire towns have folded on my regular routes through parts of Central and SE Oregon, so it is not uncommon for daily riding distances to be much longer than planned.
If you can lay in some stores of food and water to tide you over past an unexpected closure, it makes for a good bailout plan. If you see a "No Trespassing" sign, be sure to heed it and move on to an unsigned area.
The good news is the weather throughout this next week on the coast and in the Valley looks to be fantastic and the coastal winds should generally favor your southbound travel. You'll be in for a real treat in terms of scenery.
Do take care and know all good wishes go with you for a safe, happy Adventure.
All the best,
Dan.
