Bob, you'll get away with a number of tunings on most stringed instruments. You could try tuning to the top 4 of a guitar but I'm not sure about string tensions with a mandolin set - the E could stay the same but the worst, one bottom G on the mandolin which would have to go up 7 semitones to make the D.

Besides that, std mandolin tuning, GDAE is a great tuning - well worth learning I think (but I am biased playing mostly tenor banjo and mandolin).

Jon