Congrats on your half success!
I ran the half (my first) in 2009 and then ran the full in 2010. In between, I didn't do any other long distance races--that's just me. I don't go for quantity in races, it seems. So I made the jump from half to full after just one half--- no other halfs in between
Deciding you want to do the marathon--and getting over the fear--is the first step, so you're on your way (snd is forking over large cash to Disney

). Believing you can do it is a BIG deal.
After I did my half, I took a few weeks off (ITB) and then decide to do a spring "fast 5k" (which, as we all know, is a very relative thing!). This let me keep a base of miles going that weren't too bad and also gave me a goal. (I am very goal-oreinted). That took me through the early spring and then I decide to try a sprint tri. So I changed up my training--which is refreshing--and did one in June. Summer, I decided to start to build my base back up, so I did part of a half marathon plan that I had. Did a Muddy Buddy (on a whim). By the time Labor day or so rolled around, I was able to start my marathon plan with the right level of base.
So I would say do the following: take some time off to let your body recover. Find a marathon plan that looks good for you. I would do it now because even though you won't be using it now, you will be able to plan around it and make sure you are ready to start it. Then spend the next six months or so working on keeping some kind of base, and maybe throwing in a small race or two to keep you motivated. If you like running halfs, you could do another one, I suppose. But IMHO, you don't need to. Plus, you want to be in good shape to start the marathon plan in the fall.
As for race experience/fatigue/etc. Well it's tough, for sure. But I recall at mile 10 of my Disney half, I wasn't sure I was going to make it! This is why we train. And try not to judge and project forward when it comes to training. Don't get in the trap of saying "That 13 mile run was awful. How will I ever do 26.2" Every run is different and a race is different from training.
Sorry to be long winded. Hope this makes sense and hope it helps. If not, I'm sure others will chime in!