There is not really anything that can actually replace the pool but I usually recommend that people use either the row, jacobs ladder, or versa-climber machines as a substitute since they are low impact and full body workouts.

Deployments are 4-5 MO and TDYs can be days to months most units will deploy every 18 months. Typically they try to not make guys with families gone for extended periods of time, but the mission dictates what you need to do so just like everything we plan for the worst and hope for the best.

You will be able to do all of it if you're going to a place with a pool. I have had many clients complete the land portion of my workouts while deployed, then restart and do the program again when they get back home and have access to a pool since you have access to the programs for a year and restart without having to pay for up to a year from your purchase date.