The last few years, due to money and kid considerations, we just hung out together. Sent the kids off to grandma for the day and just sat around at home this year. Well, we did some stuff together, but nothing big.
But then, this was our 15th.
If you want to "ramp it up," why don't you make plans? There's nothing to say it must be all the guy (except some silly tradition that it's his job), and then you can be excited AND satisfied afterwards. Just an overnight at a romantic B&B, or dinner at a nice restaurant, or even a day at the park. Again, being together is the most important thing. And if he's gone for the day of (sometimes work can't be gotten around), plan it for as soon as you can after. Nothing says that it has to be the big production on the day of. Same thing for b-day or valentines.
In fact, maybe you can plan something to surprise him with when he gets home from this trip - a belated anniversary celebration.
A few years ago, my husband was on the road for our anniversay, so I know how this feels. I was happy to hear from him and that he remembered.
As far as the flowers, I would relax. The more you bug him the more of an issue it will be. Some guys just aren't flower-givers; it really has nothing to do with his level of affection, it just isn't something he thinks of. Don't let it be a point of contention.... in fact, I've gotten my husband an boquet of flowers before (not roses, but one of the other bunches) and bought myself flowers a couple of times. Every so often he will surprise me, but flowers can be really expensive!
Just remember - it's the people and relationships that matter, the rest is fluff :D
Good luck!