Here are multiple ideas for outdoor time.
Here is a link to a great idea resource for "catios". CLICK HERE.
Here is a nice harness for kitties - I recommend playing with your kitty with a wand toy while practicing in the harness.. he /she may associate the two! http://www.pettravelstore.com/tsa-fast-pass-leash-harness/
Outdoor enclosures can help you and your cat .. here are some ideas below and a whole lot more on this Swedish site :
http://pawpeds.com/pawacademy/management/catrun/
Some are big, some are small and portable.. .. please send me any ideas you want to share too!
Click on the tunnel photo above for purchasing information.
Oh and a good site for cat trees for large cats:
http://www.maine-coon-cat-nation.com/cat-furniture-tree.html