: So if any of you have heard about stuff like this, or you have a neat idea to
: contribute, or like me you get bluebrains and need some periodic mental
: masturbation:

From the description of your problems and what you're "not" supposed to do,
My first thought is to build a small catamaran hull with a recumbent style
bicycle seat/peddling steering rig. I've seen a set-up with a regular bicycle
and pontoons, but it makes more sense to use a recumbent style.

Or you could canoe sail.

I have a lot of friends who are older than me (54) and we are all veterans of
white water paddling, sea kayaking, skiing and hiking/backpacking.
We all have injures and keep going at some level.

My experience with doctors is that most are accustomed to very sedentary clients.
Such doctors are likely to under estimate your powers of recovery, especially when
dealing with stubborn outdoor nuts.

The more ideas you have or listen to the more options you will have. Sometimes
ideas perceived as crazy will work. I remember a Boston white water paddler who
paddled a canoe and had bad knees. He could not kneel in his open canoe and didn't
want to paddle a kayak. So he built his own bigger white water canoe which he
stood up and padded in! Everyone thought he was nuts at first. But he did it!

You could pole your kayak. Think I'm kidding?

I met a guy who poled canoes and he crossed lakes by spinning his pole
like a kayak paddle.

Desire and tenacity will overcome just about anything.

All the best,
Rob