I've done the drive from DC to Walla Walla a few times. It's pretty straight forward. 90 to 80 to 70, then drop down to DC on 270. The other option would be to drop down to 80 earlier and come across the southern part of wyoming etc. Either way it's not real exciting.

I was driving a diesel when I did that drive but it was an old VW diesel rabbit. I went from DC to Walla Walla on less than $80 in fuel. I spent more on beer and food. Needless to say it was a long time ago.

 

I would plan timing through the I-90 Chicago metro stretch quite carefully since you will be towing with horses. It would seem hitting it very late or very very early a.m. or even on the weekend would be best to avoid traffic tie-ups. Maybe someone from that area can better advise.

 

I had a suggestion to catch I-74 at Daveport, IA, then take 70 from Indianapolis into DC. I'll avoid Chicago and Cleveland, but add about 70 miles to the trip. You think it's worth it?

 

I don't think an extra 70 miles out of a possible 2800 mile ride is a big deal, especially if you can ease any rush hour traffic aggravation.

On your way East on I-70, near Pittsburgh I'd turn South on I-79 and then take I-68 East into the Baltimore/Wash DC metro area rather than taking the PA Turnpike all the way to Breezewood (City of Motels) before diving south. I've done that trip about a zillion times and even though its a little longer, its much more relaxing than fighting all the 2 lane semi-truck traffic and never ending construction on the PA Turnpike.

I've never pulled horses, so there may be other concerns that I am unaware of.

 

Someone suggested that as well, however they said that I-68 was too hilly for their tastes, that they'd prefer 70. I remember the PA Turnpike though, and I'd rather fight hills all day than that traffic and construction again.

Pulling horses isn't too much different from any other load, you just have to be a little more gentle with your movements; the horses don't like it when you slam on the brakes or take sharp turns! In our old bumperpull, I used to be able to feel them start kicking everytime we hit a big bump.