Where will you be touring? I haven't had any problem touring on 25s as long as the roads are paved or decent gravel. But I wouldn't want to go on rocky fire roads or muddy trails. And keeping your load as light as possible would help avoid pinch flats with the skinnier tires.
I've been satisfied with pretty inexpensive tires from both Nashbar (house brand Prima) and Performance (Forte) and try to get them when they're on sale for under $10. Haven't noticed much difference in either durability or performance between these and much more expensive tires.