It is not too difficult, but I would recommend getting a Clymer or Honda Service manual and looking through the process and tools before you tear into it. It also wouldn't hurt to invest in a service manual, this won't be the only time you use it. I would recommend
Motosport Outlet (link) for the parts. They sell complete motor kits (Hot Rods crank, crank bearings, crank seals, engine gasket set, top end set) I would also recommend locating a seal set for the motor (it would include kickshaft seal, shiftshaft seal, counter shaft seal(s), crank seals (these would end up being extra, but it never hurts to have extra crank seals on a 2 stroke) and water pump seals).
Midwest Action Cycle (link) usually has these. Good Luck