I don't know the last time you dealt with cat litter and litter boxes, but there have been some dramatic advances with both. Clumping litters and crystal litters all but eliminate the smell completely. And without spending a lot, you could get one of these rolling litter boxes that mean you wouldn't even need to scoop. (Caveat: I haven't used one of these, but I know people who love them.) That said, there is the possibility that you get a fussy cat that doesn't like certain types of litter. So while I can't guarantee that you won't have problems, I'm pretty confident that with a bit of experimentation you can find a solution that both you and the cat are happy with.
I am a firm believer in keeping cats indoors; they are safer and live far longer than their outdoor counterpart. That said, if you're want to adopt a cat from a shelter, you'll be giving it a far better life, even if you let it outdoors, than it would have in the shelter for the rest of its life. So if the choice is between having no cat and adopting a cat that you allow outdoors, go for the second option.
Also, most shelters will give you a trial period where you can return the animal if it doesn't work out. If you're not sure how well you can cope with the smell, you can use the trial period to find out. Or you can foster a cat for a limited period of time. That way, even if you find the smell objectionable, you know it's only for a short time.
Finally, don't underestimate the power of love. When you feel that unconditional love from an animal, cleaning up after it doesn't seem like nearly as much of a chore. I'm living proof. Frankly, I'm not a neat person, and my home is always a mess. I detest cleaning. But paradoxically, the litter boxes get scooped and cleaned regularly, and I don't mind litter duty.