ORIGINAL: goos_blues
.243 would be pretty good and you could use it for varmints also.
As you could also with the 2506 he mentioned as well. Of the 2 - 2506 would be my choice.
200 yards max and deer sized the options are large. Something to consider maybe checking local area for ammo selection(assuming you won't be reloading), this may help narrow the field somewhat.
Just a thoughtseeing you are thinking about an encore platform have you consider a 50 cal ML barrel?? Being you live in a shotgun area it is likely it can be used now and in the future you could always add CF barrels if desired. As an ML capable to reach 200 yards with practice and finding the right load combo!
PS forgot re:scopes. I am of the thinking scopes and mounts are not the place to save a few bucks. For a big game rig I like a starting point of the bushnell elites or equiv (approx 200.00) and going up to whatever your eye, heart and budget can allow. As far as the mounts go I personally like/trust Leupold and Warne Maxima. The majority of my biggame CF's wear Leupold Double Dovetail's.If an ML is of interets I suggestlooking atWarne Maxima Quick Release, IME excellent on my inlines &highly reccomended.
Good Luck