Even though I've only been living up in Muskoka since January, I can help everyone out with this dilemma!
The first thing to decide is where you want to have the get together. Huntsville is about 20mins from Dwight and you can pretty much forget about cabs to get back and forth. It's not that they don't exist, just that they are hard to arrange and very expensive.
In Huntsville the best pub/watering holes are the already mentioned "On the Docks" pub and the Cottage Waterfront Grill (http://www.huntsvillecottage.com
) which is just across the bridge from On the Docks. The Cottage is probably the best choice for a big group. On the Docks is pretty small, unless the weather is nice enough to sit outside, and on nights with a band it gets even more crowded. They also don't have a fryer for those that are fans of deep fried food!
If you'd prefer to get together somewhere closer to Dwight there is Muskoka on the Rocks (http://www.muskokaontherocks.ca
) in Hillside, about 10mins from Dwight, and the Bush Company (http://www.thebushcompany.com
) which is only 2mins by car from Axiom. Both have excellent food with Muskoka on the Rocks being a great place for steaks, ribs, etc. Bush Company has great wings, sandwiches, fries, etc. In terms of beer selection, Muskoka on the Rocks has some usual suspects like Keith's, Coors Light, along with Boddingtons and some microbrews like the local Lake of Bays IPA and Big Rock Brewery Ale, from Alberta. Bush Company only has Bud, Coors light, and Keith's and Keith's white on tap with a larger selection of bottled domestics and imports.
If anyone has any questions or would like more details, please feel free to ask.