Front derailleurs only extend so far. if it doesn't reach, you need a new one. Assuming a 68mm BB, I nearly always chuck the square taper cranks and the bottom bracket, and replace the whole lot with a Hollowtech one (M590). I fit the PAS on the left side so that it doesn't interfere with the gears. Those cranks, including the BB, are about £60 and it it gives you the chance to go up to 44T or 48T on the big chain-ring for relaxed pedalling at speed. The whole system is lighter, stronger, gives better gearing and gives me a reliable predictable way to fit the PAS, so it kills several birds with one stone. Also, your cranks never come loose like square taper ones sometimes do.
You can run without the front derailleur. Carry a lolly-stick or similar, so that if ever you need to run with the smaller chain-ring, you can hook the chain over. it only takes a few seconds. That's what I used to do. On nearly all my rides, it's downhill on the way out and uphill on the way back, so I hooked the chain over before coming back. Once on, it doesn't come off.
