There is a 2000 foot drop /climb from Keene to Lake Placid so you will get your exercise..Some of it is two lanes the same direction ,some not.
Whiteface Mt is a must see. Its an additional 3000 foot climb so its for the truck alone.
Lake Placid.. ugh. Its a tourist town and no RV parking handy. it is a nice town off season ( I have friends there). The traffic downtown is brutal but downtown is just a little short of a mile long
This is a good place to start'https://www.lakeplacid.com/
Countless places to paddle in the Placid area.. follow the paddling link on the above site.
there are no superhighways going east to west and you either have to take the Champlain Ferry ( one of three) or go to the foot or the top of Champlain to take the bridge at Rouses Point or Crown Point.
Plan an average 30 mph. No reservations taken on the ferry.
You could easily spend a week in the Adirondacks.. Mt Jo is a delightful hike but there are a couple around Mirror Lake too as well as thousands of miles of more strenuous hiking trails
It can get cool in June and there will be bugs. It should be the end of blackfly season and the start of stablefly biting season and mosquito season.
I cant recommend any RV campgrounds because when we go to the Adirondacks we paddle and tent camp.
There are some State DEC campgrounds in the area that do not have hookups. However if your unit is over 25 feet it won't fit at many campgrounds. Fish Creek or Rollins is your best bet. And those are getting full
Meadowbrook is often used by RVers . Its between Saranac and Placid and is an campground in back of a loud restaurant Its grassy and the sites level except that it lacks features of any sort save an iffy shower and washrooms
You would look in Region 5 for a DEC campground
There are some RV campgrounds in the vicinity I can vouch that Charlies Inn Campground at Lake Clear Junction is fun.. Its close to walking paddling the very nice Paul Smiths Visitor Information Center on Rt 30. And not near any town
Now dining. A must is to go to Donnelly's soft serve ice cream at the junction of 186 and 86. You walk in the door and select your size cone. No arguing over flavor. The only flavor is the flavor of the day. You don't like it, try another day. However you can always get the FOD in a vanilla twist. They make the ice cream right there. Its a farm.