Personally, I've never gotten cash from a Treasure Trail (but I really only do level-1s).
last one netted me a handful of trout and a few law runes. Barely made up for the amount of law runes I used in completing it. Oh well.
Anyone know what the best way to get clue scrolls is? Being lazy, I tend to stick with the ones I get from my Miscellania loot or the occasional pickpocketing spree. I really just do them for fun, as I know the profit margin sucks.