We fulltime in a 25' class C, don't have a toad and very rarely regret not having one. In my opinion a toad will not be helpful at all in Alaska unless you are planning on going out into the bush and then a jeep or other 4 wheel drive vehicle as your toad would make sense.
The main roads make one big loop with a few spur roads so you won't be parking somewhere for weeks and taking day trips. Instead you'll be on a road trip with stops along the way. Chances are if you have a toad it will stay hooked up most of the time, just taking abuse from flying gravel and other road debris.
I have a lot of information about Alaska on my blog including details about parking a RV at attractions. When you get the bottom of the posts click on "Older Posts" to bring more Alaska posts up.
http://rollinginarv-wheelchairtraveling.blogspot.com/search/label/ALASKA