When I was 25 that was the bike I did a two week tour on. Maserati road bike with 74degree head/seat angles. I changed the front fork to one with more rake. Put on a blackburn rack with ss. p. clamps. Rode on 19mm wide Rigida rims, 36 hole,straight 15g. spokes. But I weighed 145lbs and was carrying less than 15lbs. My riding partner was 6'4" 180lbs and had similar bike but with 14g. spokes on the rear. We weren't carrying much weight and rode on 700x28 tires. If you need money for the trip I wouldn't bother sinking it into a new bike as long as your road bike can be made to work. A new or rebuilt rear wheel is still a lot cheaper than a new bike.

If you're a 220lb+ rider wanting to load up an old road bike with 30+lbs and both wheels are dodgy and the gears need changing then looking around for that old mtn bike built on coop parts start making a lot of sense. For touring speeds 26"x1.5 touring tires roll very nice over all kinds of garbage compared to skinny tires.