In addition to the OPK's, you can also try tracking your BBT (basal body temperature). This will give you a pretty clear idea of your cycle. Also reading the book, Taking Charge of Your Fertility should tell you just about everything you need to know.
It takes aprx 3 months for eggs to begin to ripen before final ovulation, so it's best to start now treating your body as if you were already pregnant. For best success, you should be at an ideal body weight/bmi and no smoking or drinking. Eat the right foods and take a prenatal.
Best of luck!
Well, let's see, if you're planning on trying to conceive as soon as he gets back, I would probably start taking prenatal vitamins, and once he gets back, maybe buy an ovulation test kit, so you can pinpoint your fertile days. Best of luck!