As long as you give her a very good once or twice over you should be fine. I did almost 13k last year in 2 months. I went everywhere, from over 12,000ft in CO to death valley, and the only issues I had were the brushes wearing out on the voltage reg. and I had to drive 150 miles with zero electrics.
I do have a turbo on my 240D but I think you should be able to do ~75mph most of the way as I did, and what ever she will do (~45-65) on the really big hills out west.
I do 8-10K miles between oil changes, but I'm using Pentosin full synthetic. I would change it at 4-5k miles if its the reg stuff. Just make sure you have a good filter, (Robbins in Nashua, NH carries Mann), and check the level every other fuel stop. I used something like 1L/4k miles.
Oh, one thing I found out is when you stop and fill up at the big truck stops you usually get free coffee when you buy diesel. I told them I was only getting a little amount and they said it does not matter every time
