My advice is to use the scroll's ingame and see how far you can go. From his fall point (as 'origin') you should be able to sketch (in your mind) a circle or range that he would have jumped from. Naturally i would put his house somewhere along that range.
Edit: i did this for you ingame. Turns out that with an average acrobtics skill, and using the scroll, the closest city along the arch of the jump range is Pelagiad. The jump went just a bit further so my suggestion is put his cottage somewhere in the wilderness north of pelagiad, but not too far. There is a quiet, small turret (yea i have no idea what the geological term for that is lol) of land sticking out into the lake above Pelagiad which looks ideal for a quiet cottage for a wacky mage.
Enjoy