First thing if there are difficulties figuring out the time difference...get on timeanddate.com, get the time info of the city that the other person is in, and save that page! It's the first page I open on the computer and the last page I close each day.
DH has been traveling this year as a product tester, the trips are always last minute notice and it's kind of a pain, even though we KNEW this is what was going to happen. I personally have an easier time with it compared to DS and DH. But I've always had that sort of personality, where I don't have to see people all the time to still feel close to them, and I guess it has just translated over to these trips...makes it easier on me.
But I still get tired...tired of being the go-to person. Has given me even more empathy towards my mom and other single parents, and I can't even imagine how hard it would be if I were working as well!
Routines are important. Bed times are strictly enforced, since I need my downtime.
Just a warning...I've always found it harder to adjust when DH returns than when he leaves. For the first couple years of our marriage, we inevitably had a fight within the first 24 hours that he go home. Now, I know what to expect and we are both a little more tolerant and patient with each other.
Ooh I hadn't thought about it, but the routine thing is very true for me!
And I have a harder time with him getting back as well. We're working on the cause of it...starting with us actually going into the airport instead of just picking him up at arrivals. Otherwise he gets in the car and tries to give out any souvenirs he's brought and that just doesn't go well (what's left to do when at home, ya know?) and he's usually exhausted by carrying his bags etc. So if we go in, we have an hour from park to pay to meet him, help carry luggage, snag a coffee (Seattle has "street pricing" on food, so it's not more expensive than going to a non-airport Starbucks or wherever), and then relax while we leave. Sure, it's an extra $3 for the parking, but it has really changed our pickups!
But since this seems to be just one big trip, that stuff probably won't happen. So just find your routine...and be happy with it. IF you're the neatfreak and he isn't, be happy that you can pick up all the time and no one will mess with it.

If you're the slob (as I am) then be happy in the slobbiness...well, until the day before he gets home, then it's deep cleaning time!
We had already started using a budget for expenses, and have a budget for "family fun"...DS and I definitely use more of that when DH is gone, and we don't feel guilty. Hubby is off dining out (and getting bored with it) and having everything paid for by the company, so if DS and I want to go to restaurants more often, we do it! Movie rentals as well. Going to the zoo. etc etc. We have to amuse ourselves!