indyfabz - no (on shortening the chain). The chain length is set by his big-big combination (48+34). The OP doesn't need a longer chain. If he needs to shorten it to accomodate small-small combos with 2 fewer teeth (26 to 24T chainring), I'd try to avoid the small-small combos first as it's easier to recover from a dropped chain (greasy fingers) than a locked-up drive train (greasy fingers, some dissassembly may be required, broken derailluer, damaged chain!).

Is a 7% plus change lower gear worth the cost and effort to the OP - it's up to him. The same "expense" reducing weight of gear carried (or as I suspect many of us including myself - carried by the 'motor'!) would pay off throughout a hilly ride, but he knows his terrain and abilities better than we do.