With one year's pay and time off — the whole world is your oyster! Which pretty much makes your question impossible to answer — except folks telling you stuff that they have done or wish to do…
Not exactly hiking — and maybe not even your cup of tea — but who knows? Still my all time favorite trip after all these years is the seven-month RTW trip I took back in 2009. How big is our world, really? You can't feel its size flying from continent to continent. So I did the whole trip by ship and train.
One (of many) highlights of a very long trip is the "zen" feel to it. I reckon this is similar to running marathons (after you overcome 'the wall') or doing long through hikes. Much more than just the feel of settling into a new routine — after 3-4 months on the road — going from hostel to hostel to more hostels becomes the "normal" while the very concept of "home" fades away! I felt a sense of freedom and detachment that I have never felt before. I felt completely at home, whichever location I might be at any given moment. I honestly did not care at all whether I continue traveling or return home or whatever.
Anyway, a very long-winded reply to suggest — given this rare opportunity of both time and money — to try an entirely new experience — don't just hike your own neighborhood that you can do almost any time — but do something entirely different. YMMV, of course. Best of luck in whichever adventure you choose!
