I've seen very few 'alterations' to the AC for that. What I have seen though are suggestions to clean the AC's tray and make sure the drain hole is unplugged. Then tilt the RV using the jacks to the place you would prefer the drain water to head for. Most of the time it was right front for the front AC. Than an alteration would be to get a set of those RV gutter extensions that slip into the edge rails, which are tiny gutters. Get creative, drill a hole and add a screw so they'll stay in place (I tried those extensions twice and both times the wind from driving blew them out so they're on the freeway somewhere).
I've since moved to an RV with a basement heat pump so don't worry about that drain water any more. During the time I owned my Bounder though, it wasn't all that bad as long as I 'directed' the water to a certain spot near the front right corner. Couldn't even see any streaks usually. If that wasn't possible, than I'd have light white streaks on the LR window.