Here's how I think the remaining level exits should be done:
In the current level, just hug the wall as far right as possible.
The next level, the river, has exit at x = 6364.
Best starting x-position I was able to get is 3190 by hugging the right wall.
But y-position is leathal due to the deadly river.
With the elevators, we can get lower y-position, but not higher.
Getting low enough allows going below the river and avoiding death.
However, it takes too long to fall through the whole level.
Luckily, Taz can start from where he dies on the river, so it seems that dying here once is necessary.
Strangely, visiting the continue screen allows glitching the river, so that it won't kill Taz:
http://dehacked.2y.net/microstorage.php/info/522648644/TAZ-river-testing.gmv
Even stranger: the effect is permanent, so that the deadly pit in the next level stops working too. I was not able to replicate it in other levels. Anyway, dying three times takes a long time and spinning through the glitched river takes even longer, so the glitch can't be shown in the TAS. Oh well, at least we skip about a half of the river level.
For the plant boss level, it looks like starting from the normal position is the best alternative. The second best solution is going as far to the left as possible and stand on a log. I was able to get x = 5950, but it is way too far to the right, because:
Normally, the plant boss level begins at x = 114.
And the boss x-position is about 1750.
So, it is only a short distance.
The rest should be easy:
After plant boss dies, we want to go as far to the right as possible.
After the first temple level ends, we want to move as far to the left as possible, because in the next level we are forced to start too far to the right. (We could also fall through the second temple, but it seems slow.)
At the second temple (which mostly needs to be played normally), we end so that we start on top of evil taz twin.
After evil taz dies, we want to go as far left as possible, which means hugging the left wall of the boss room. This way we can start near the final boss.
(Most of these are shown in the river glitching GMV linked above.)
