Tip: When determining a time limit, remember that players won't be as familiar with the level as you are. If you normally complete the level with around 100s left on the timer, others might run out of time on their first try.
The main level data loading routine.
$05DAE5 is which level has the variable exits that changes depending on coins, timer, and yoshi coins. To disable the variable properties of this level, change $05DAE6 to 80.
$05DA19 is the start of the code for checking whether or not the level should use a No-Yoshi intro. Change to [4C D7 DA] to disable all No-Yoshi intros, including those for ghost houses and castles.