It largely depends what you want to do. If you just want a "different sounding mini-guitar" then go for it, but a couple of things you ought to be aware of:

Firstly- you wouldn't want to use off-the-shelf mandolin strings, because you'd be tuning three of the pairs of strings higher than their intended pitch- a tone, a fourth and a fifth respectively. Ouch! Your fingers wouldn't thank you, nor the mandolin.

Secondly, there are good reasons why a mandolin is tuned the way it is- tuning it in fourths gives you way less range (a 5th) and you may also find the fretboard is a little tighter on space this way.

Have you thought about a bouzouki? The standard Greek tuning is CFAD, a tone below a guitar, with octaves on the lower two courses- but a lot of players tune up to match the guitar. It's an octave lower than a mandolin, but with a longer scale-length, and of course the familiar tuning, you could easily play up the neck into mandolin range.