It depends on what you are looking for A
catch and release or keep, a lake that is fairly challenging but has bigger and harder fighting fish, or a lake that is less challenging with plenty of smaller fish?
Tunkwa Lake Resort is a good choice, it does offer boat rental, the owner and caretaker will always do their best to accommodate the visitors since they're also fishing nuts. The small cabins are cozy with shared bathrooms between all the cabins. The larger cottages are super comfy but are more suitable for a large group. The fishing can be good, but it can be a challenge... The lake gets windy, fly fishing can be moody even for those who think they have the flies figured out. Trolling for these fish can get you into some fish, but not as good as fly fishing if a hatch is happening. Fish size ranges between 1 to 4lb average, with the odd bigger ones around, and they fight very hard.
A closer one to go for is maybe Onion Lake at Ruddocks Ranch. My understanding is that the owner is not offering cabin accommodation this year, only lakeside camping for those who wish to tent or bring their own camper. It's a catch and release lake, and fly fishing only. Fishing is generally pretty good, plus it is limited to 4 boats at any given time, therefore you do not have to worry about fishing pressure. They also have boats available at the lake. You should be able to get a day rate for camping and boat use from them.
Closer to home, maybe Alta Lake in Whistler where I was just at last weekend. Boat/canoe rental is available at Lakeside Park, I'm not sure how much it is. Fishing is relatively easy, with lots of small rainbow trout (but fight harder than urban stocked rainbows) and the odd big cutthroat trout. This is another catch and release lake, with a bait ban but you can use lures if you choose not to fly fish. It might be a good place to go if you want to bring them to Whistler for a couple of days of sightseeing.