I assumed it was on Mull from the ad, but Iona would probably work if you were willing to open up B&B or something tourism related, lots of visitors in summer and stunning in winter.
Would be too much physical demand for me to take on but location wise I'd have it like a shot, I love the islands and the mix of isolation and visitors coming in would suit me.
I know, give me enough grazing and handling space for my stud and a wee workshop/coffee shop and a log cabin or static caravan onsite, and I'll make you a bit more income, caretake your ponies and whatever else whenever you crave the mainland - sorted
Failing that I'm buying a lottery ticket