Changes, continued
The sand seemed too dark orange. Changed out 740 Tangerine to 742 Light Tangerine. This seems a lot closer to the color I saw in game. Although, I will say I think the block next to the water that uses the same color scheme looks better with the darker color (I might replace it later).
For the cactus, I used 906 and 909. There is a brown version in the first level of world 2 that I think is supposed to be burnt.

- cactus and palm- burnt.png (1.36 KiB) Viewed 5444 times
However, I prefer the green version that is found a little more often in game.

- cactus and palm2.png (1.68 KiB) Viewed 5444 times

- cacti and palms 2.png (2.19 KiB) Viewed 5444 times
(From Map by Zeric - VGmaps.com)
For some reason I often see the Hammer used as the power up for Hammer Suit Mario online, but that's used to break rocks on the maps.

- rock.png (1.92 KiB) Viewed 5444 times
while the power up to give you Hammer Mario is actually a little suit like the Frog Suit and Tanooki Suit power ups.

- power up bar.png (6.56 KiB) Viewed 5444 times
(emulator)
So I replaced the Hammer with this Hammer Suit. I haven't got the color to fill them in yet, but I will probably use 3852 (Very Dark Straw).
I had problems finding a sprite, but found a copy of the all-star version on the Mario wiki and used it to draw a copy with the original NES colors.