I grew up in Roseburg (about an hour and half north of Medford) But I remember Medford consistently being 10-20 degrees hotter than us during the summer months, I'd plan on 90-110 depending on how the summer is. I haven't spent much time in Medford unfortunately so can't give you much advice on it besides that, Crater lake is beautiful, an excellent place to visit, and makes for some great pictures, but you can't do much with the lake (it's very protected, no swimming, no boating, etc) However I would highly recommend checking out Diamond Lake while you're visiting Crater Lake, it's probably 20-30 minutes away (you might even pass it on the way up to Crater Lake depending on the route/direction you take to get there. It's a beautiful area, with a nice lodge/restaurant cabins you can rent for night, camping area, paddle and motor boat and bicycle rentals (it's a nice 11mile loop around the lake with a mostly paved bicycle path all the way around it. They also keep the lake stocked with trout (I caught a 19" last time I was there and all three of us caught our limit). I know the rogue has some good white water rafting and innertubing as well, probably some great fishing.