Hi James - glad to see some from from Jersey here too! We just purchased our property in May, and listed it last week so it's a little hard for me to say right now, but I can tell you what I researched and what I learned from talking to local PMs.
So far we have received 6 bookings I think, and declined a few because they didn't meet our requirements of having multiple positive reviews.
Before purchasing the property I purchased the data from AirDNA to get a sense of what a house, similar to the one we were buying, would do in terms of income per year. Most of the local realtors and PMs told a common story that April and November are the slow months, people usually book long weekends, and it's harder to sell the days mid-week so you have to lower your price.
We also own a cabin up there that we don't rent out....and have been going there for over 20 years. Based on that the above seems pretty accurate to me as we've been there very month of the year. Late Nov-Mar with skiing, May-Sept hikers and bikers and paddlers, Oct is leaf peeping/hikers/bikers.
From what I know there are A LOT of short-term rentals...but that shouldn't necessarily be a road block as it's just a matter of asking a better question of "What kind of property should I look for if the market is saturated?" For me we looked for a property that has an "unfair advantage" (term I heard on a podcast....maybe BP). "Unfair advantage" meaning what is it has features that not every property is going to have? For us it has woods, acerage, picturesque cottage with stone fireplace. So my suggestion would be to do the same thing and not just go for the ski chalet (unless you get a beautiful deal) since there are so many of those and go for a niche property instead. This is our 2nd short-term rental, and from what I learned from the 1st is that people don't want to stay in a home that looks like their home. They want a unique experience wrapped around the property as well and the more you can give them that unique experience, the better you'll do in a saturated market.
Hope that helps. Please feel free to ask any other questions!
Mike