Just to add +1 on the recovery front, don't over do it.
As a morale booster I can tell you that I've been riding for several years, have a shiny summer carbon road bike, winter road bike etc. etc.
Although I'm not exactly svelte, I'm quite capable of 75 mile rides however haven't ridden since about September for one reason and another (arrival of first sprog etc.) and just this week I've got back on a bike and started commuting for the first time. I've always avoided commuting by bike because cycling has always been first and foremost a leisure activity for me, to de-stress away from work etc. However the new family means I won't be able to vanish for hours at a time on the bike for a while so commuting it is.
It's 11 miles each way with a few short/sharp hills (this being Devon). Takes me about 45 mins in the morning and around 55 mins home (slightly longer route) and I've done it twice this week however tomorrow will be in the car to let my body recover and I'll either commute again Friday or if time permits a longer ride at the weekend.
In summary, as a new rider, doing a 28 mile round trip commute, on an MTB with knobbly tires, sir, I salute you!
Good luck,
Paddy