Slokey - I think almost all of your runs are off-road, in a bid to protect your failing joints etc? Same here. The slight problem with this cunning training regime is that our marathons will be run on the road. I had planned to become concerned about this, but then I changed my mind.
There isn't a deep end at my local pool, so the water's about chest height all the way. I just run up and down the length of the pool (25m) for as long as seems sensible. As Moof suggests, it's not a particularly good look, but you soon get used to the sneers of encouragement from fellow pool users.
Minni - I'm a great advocate (née, bore) of pool running when injured. I can't claim it's a particularly fun-filled pastime (mind you, neither is road running) but it does keep your limbs tuned in a vaguely runnerly direction.
Certainly, it's a lot less tedious than the turbo. Cross-trainers are generally good, I suppose, but they usually involve gyms, soundless televisions and eye-wateringly awful music.