Tip: Remaking levels from other Mario games is strongly discouraged, especially popular ones (World 1-1 from SMB or SMB3, for example), as their over-presence in Mario games, official or not, often makes them uninteresting to play.
The routine that updates the values of all the addresses used for the status bar ($0EF9-$0F2F).
$008E28 - Change this address to AD to disable the timer.
$008E2E - Timer speed (USE WITH $008D8B)
$008E5C - Time is Running Out SFX. Change from FF to 00 to stop the music from speeding up when time reaches 99.
$008E6B - [22 06 F6 00] Change to [EA EA EA EA] to not kill Mario when the timer reaches zero. The timer will count down normally and stop at zero, but Mario will not die
$008EDB - Change this and/or $008F09 from 20 12 90 to EA EA EA to disable writing the score to the status bar when playing as Mario and/or Luigi, respectively. Useful if you want to place another counter in place of the score using Smallhacker's Status Bar Editor. Note: This alone will NOT stop writing blank tiles if the first N tiles/bytes at $0F29-$0F2E contains the value #$00 (the "0" graphic). To prevent that, consider using this patch.
$008EE3 - Change to BRA  to write zeroes instead of blank tiles to Mario's score counter. Use with $008F11.
$008F11 - Change to BRA  to write zeroes instead of blank tiles to Luigi's score counter. Use with $008EE3.
$008F2C - How many coins you need to get an 1up (USE WITH $008F37)
$008F2F - [EE E4 18] Change to [EA EA EA] to not gain a life after collecting enough for one.
$008F37 - Number of coins to subtract from the counter when you gain enough for a 1up (Default: $64 (100). Change to  to create a coin wallet effect - use with $008F2F.
$008F41 - (Use with $008F45) Maximum life limit, minus one. Warning: Changing this to anything higher than 0x7E (127 lives) will remove the life limit entirely! Also, if you have more than
99 lives, the life counter will appear slightly glitched.
$008F45 - (Use with $008F41) Maximum life limit, minus one. Note that if you have more than 99 lives, the life counter will appear slightly glitched.
$008F62 - Number of bonus stars required to enter bonus game
$008F67 - [8D 25 14] Change to EA EA EA to disable entering bonus game when player has 100 bonus stars.
$008F6F - Amount of bonus stars that will be subtracted when 100 bonus stars are collected. Change to  to make 99 the maximum amount of bonus stars you can get - to create a bonus star wallet effect, use with $008F67.
$008F7E - Writes coins to status bar. Changing to [EA EA EA EA EA EA] will disable the coins from being written to the status bar.
$008F95 -  The X position of the small bonus star counter in the status bar.
$008FC5 - [20 79 90] Change to EA EA EA to disable the item GFX in the status bar
$008FCE - Length of "LUIGI" text (Status bar)
$008FE7 - [FC](blank tile) Tile used on the status bar when there's no Yoshi coin in that spot.
$008FED - [2E](coin tile) Tile used on the status bar when there is a Yoshi coin in that spot. Change to [FC](blank tile) to visually disable collected Yoshi Coins.