Middletown ,california

If you're on I5 there's the TA, Loves and Rotten Robbie at Exit 407 and then the Flying J in Lodi at the jct of CA12 and I5. I found plenty of parking at the TA.

 

best to look on the rand mcnally atlas.

 

My atlas shows the designated route to Middletown to be north on I5 to exit 578,west on Ca.20,south on CA.53 which runs into Ca. 29. There is like a 17 mile stretch on Ca.29 between Calistoga and Middletown that is not a designated route. Could be a really good reason for that. Never been there,but in those mountains there could be switchbacks,hairpin turns,who knows. I would not chance it. Tear up your truck or trailer or maybe yourself. Not worth a couple extra miles.

 

Lived in Caistoga for 30 years and had a small tow service. That 17 mile section of 29 is not a desirable choice as there are hairpin turns but the worst part about it is the traffic. Early morning and afternoon commuters race up and down that stretch. Have witnessed flat bed trailers walking over cars in those hairpins. In January and Febuary there can be snow and or ice at the summit. Haven't been up there in awhile so I can't remember the kingpin lenght restrictions.

 

Go to this wesite and click on area 1, 3 and 4. It will show the truck routes in the areas you are looking at. Looks like you need to run north on 5 to CA20w to CA53so to CA29.
The lower part of CA29 off 80 shows 30' kingpin.
http://www.dot.ca.gov/hq/traffops/trucks/truckmap/