We toured Alaska in a 26ft B+ without a toad and were glad to be toadless. It really depends on how you spend your time and your goals.
We took a number of ferry trips with the motorhome and it would have been much more expensive and difficult to fit if we had a toad. Getting into some camp sites would have been more difficult with a toad. As we were traveling more than camping we didn't miss a toad.
We got very dirty on some roads and it was much easier and cheaper cleaning up without a toad to wash. We saw one toad that was so covered with oil/dirt from the chip seal road construction stuff that you could not tell if it had windows or what color it was. I personally would not tow a nice car/suv to Alaska, maybe a beater ;-). We made sure we washed the RV frequently when traveling in areas where there was chip seal road construction.
Great trip...we tried to keep it simple as see a much as we could.