At the rear you have an obscelete pattern but you can still get compatable rings. Is it Shimano or some other hub. Is it a screw-on freewheel or a splined freehub design with a locknut (engraved with "Lock->")
Marchisio allow you to select each ring so build up the cassette with a wide range. A 12-28 is good for a light load or unladen mountain climbing.

Your crank will limit the smallest cog you can use because of the diamter of the bolt circle.
Compact cranks have a circle of 110mm and can take rings down to 34 t. A 34/48 will carry you up most mountains but you will probably freewheel down the fastest descents.