If you ride 40 mile one way you will earn your new lights very quickly due to lower gas bills. I'd say go for it provided you don' t have any heavy physical work. You will have a good trainig with a commute like this so that' s an added bonus. Main issue will be if you are willing to save money by having a longer commute. I would start with one day in the week, then two days and so on.

I would take a roadbike or a recumbent for the distance you are going to ride and for me personally i find it too long. I think i would commute by bike for a maximum of 17 miles one way (about one hour on the bike)