If it is working well for you, I'd discuss that with your doc. Why change if you're happy with what you're already doing? There's a difference between addiction and dependence. You have likely developed a mental dependence on Ambien simply because it works for you, so going without it would obviously trigger some problems. If you believe you won't do well without the Ambien, that's likely to be true, for you. Your mental state is critical in your health and well being. Hopefully your doctor will just let you stay on the Ambien since it sounds like it's working.
I have a somewhat similar situation, RLS, leg and hand cramps, and narcolepsy. It's a giant PITA. My neurologist recommended I try Turmeric for the cramps and it works. It's pretty crazy, but it works. I take six caps a day, my husband takes four. My sister also had leg cramps and she tried it and said it worked for her too, so no reason not to give it a try. I buy Turmeric in bulk and cap it myself or it'd be a bit expensive but when I don't take it the cramps come roaring back. I take Ropinirole HCL for the RLS and I don't think it helps much, if at all.
I looked awhile back at alternatives for RLS and there were none. They all have similar side-effects.
Someone else mentioned Calms -- a homeopathic remedy. I've used Calms since the 70s -- it works great for those waking up in the middle of the night situations. For me it simply calms my self-talk and anxious mind (can't sleep, ug!) and I'm back asleep. I'll admit I fall asleep rapidly due to the narcolepsy -- it usually takes me less than 10 mins.