I am looking for some ideas for must see and things to avoid on a 3000 mile road trip.
From Seattle to LA and back home through Vegas, Utah, Idaho, MT and back to Seattle via Lolo pass.
Tentative route is Seattle to Grants Pass then over to Crescent City, Ca to 101 to Santa Rosa CA. to Santa Cruz, Big Sur then LA .
Return trip through Vegas then Zion and Bryce Canyon NP to Ogden,UT to Pocatello ID then over Lolo pass back into WA and home to Seattle .
All in 2 weeks in mid August, I know it’s going to be hot!!! I just installed an oil cooler on my 08 SG and I am advising others to do the same. Some other details, 8 other bikes 1 truck with a bike trailer camping about half the time. Some days are 400+ mile days any advice would be appreciated.

 

Have you considered cutting over to the coast at Olympia and hitting 101. 101 through Oregon is really beautiful.

 

Sounds like a great trip. I have been in many areas you are planning on seeing. It would not be a waste of your time to go through central Idaho (Boise, McCall, Riggens, Dwarshack Resevour) then into Eastern Wa through Grand Coulee and the likes. It is beautiful and can keep you off major roads for the most part. Have a great trip and be safe.

Malac

 

Have you ridden in the desert SW in August before? Not trying to be a smartass, but you've got no idea what HOT is until you ride the desert in August. It's not that it's just hot ... but on a bike the dry air will zap the water right out of your body. Be sure to have LOTS of water or sports drinks available when heading across Vegas and into southern Utah in August. Temperatures in August will be in the 105 to 110 range pretty easily.

I live in southern Utah and get to ride those spots pretty regularly. Zion and Bryce are beautiful. If you've got time and don't mind hiking then park the bike and take the tram into Zion (you can't actually park inside the park unless you're staying at the lodge). The ride through Zion is perfectly fun, and there's plenty to see from the road or just by parking in the turnouts for a few minutes. If you park the bike and leave it the rangers get a bit cranky.

Some of the best spots in Zion are actually on the hiking trails. If you aren't into the hiking then the ride up through the Canyon and into the tunnel is pretty cool.

Bryce is a great spot as well. The parking lots are closer to the canyon so you can easily access it without a long hike. Be sure to see the hoo-doos while at Bryce.

I'd also suggest the ride across Utah Highway 12 from Highway 89 through to Boulder (UT) and back up through 24 toward Richfield. I like the ride from Zion north on Highway 89 as well, but the trip over on 12 to 24 is very nice in August. You'll get up to higher elevations where it will be cooler. This ride will put you at elevations above 8000 foot regularly.

I also like the ride from Cedar City (my home) over Cedar Mountain on Utah 14 into Duck Creek and near Navajo Lake. There are spots here that will top 10,000 feet in elevation.

Another great ride in Utah in the Nebo Loop in the northern half of the state. This loop runs through the Uinta Forest. between the cities of Nephi and Payson. It will take you to over 9,000 feet in elevation and provides breathtaking views of Utah valley, the Wasatch Mountains and 11,928-foot Mount Nebo, the tallest mountain in the Wasatch Range.

 

plus one on getting off I-5 before grant's pass
101 is great through OR, both 30 in oregon and the road on the other side of the columbia are nice rides too.
or taking I-5 to 205 then getting off either at 212 or 213 and riding down the foothills of the cascades makes for a nice ride. either way good luck and have a great ride.