Why not go over the lake rather than ON the lake. You dont need a license for an ultralight and it's actually quite fun and can be landed on any surface, ice, water, or land if you get the proper body similar to that of a hovercraft. The difference is that a hovercraft's body is vulnerable to being punctured by ice chunks. You wont have this issue with a similar body with an ultralight. My grandfather is an ex-pilot (he's now 78) and he still flies ultralights and has all sorts of different landing methods depending upon the body he uses. An ultralight can land and take off in 80 ft, but I've seen him do it in 40 right on my front lawn.
Besides, wouldnt it be a cool experience?
It might not be an option for you, but it's certainly an "option" hehe.
http://backcountryaerosports.com/faqs.ydev <--- All of the most common ultralight questions/answers.
Take particular notice to TEMPERATURE. The colder it is, the more stable it is for flying which means it's great to fly ultralight in colder seasons when boat is not an option
If it were me, I'd have 4 modes of transportation. The legs on this trike are interchangable. It can use wheels, floats, hover floats, or ski's. Hoverfloats are the "all-terrain" method for trikes but they are significantly heavier. You can land them on any surface as seen below:
If if you are ok with not having the safety of a glider, you could get one of these badboys:
https://www.youtube.com/watch?v=6VaG0LQBcgY <---- BTW, the "rotor" is not even connected to the engine. It's called a gyrocopter. The Rotor is spinning on it's own. It will even spin if you kill the engine! This guy says it best here:
https://www.youtube.com/watch?v=p8IB-5PbL9U "Most aircraft below 800 feet, if the engine dies, you are left with no time to recover. But for us, we dont care if the engine dies!" Then, he kills the engine LMAO". It's a cool vid to watch on gyrocopters which can land and takeoff in even shorter spaces than trykes.
1. 4 Wheeler for when there is no/little/packed snow on the ice (usually early winter), safe enough for snowmobile, but terrible on the tracks (Another option would be an enclosed side-by-side ATV, its a wheeler with a cab basically)
2. Snowmobile for winter or if snow is to deep for the wheeler
3. Boat (this goes without saying, its the best option when its open water season)
4. Ultralight, good for the tweener seasons (Fall/Spring). Also a cool way to check things out from above no matter what the season and believe it or not, they are actually safer than sleds/atv's. They do NOT need a motor to "fly". You can kill the motor and still fly for very long periods of time depending upon updrafts and what not. Its no different than hang gliding. Just try not to land in a tree
So like the seasons, Mobility should have 4 methods when you're living "off the grid". I've lived in Alaska and this mentality of 4 types of transportation comes from those experiences.
<-- doesnt that look cool? Who needs a sled when you have one of these beasts