The clues weren't bad. The first hint in particular made me assume that Isle Delfino is what you meant, because of it being based off of Venice, Italy.
Anyway...
1. This area is desert-themed. 2. This place is far from the Mushroom Kingdom. 3. This place is ruled by a princess. 4. Many of the enemies encountered here are unique.
I was thinking Gritzy Desert from PIT because of the Princess Shroob and now your new tip makes me think of the shroobs again. I'm pretty well stumped. Let's see if any others can come answer this while I think about it.
Alright, well this hint should do it. The area in question is from a Game Boy game, which is one of the very few games in the Mario series to not feature Bowser in any way.
I'm totally blanking. I give! Unless somebody else has an answer. I could try to look this up, but that would not be very sporting. I should know this, but am spacing out. I despise deserts anyway.
1. This place is away from the Mushroom Kingdom. 2. Two rival gangs reside in this place. 3. This place has a town beneath the ground. 4. One of four heroes is located here.
Last Edit: May 6, 2014 11:52:13 GMT -5 by SolarBlaze
1. This area has a toad boy obsessed with video games 2. The mayor of this area changes by the time the game ends 3. This area maintains a pleasant climate all year round 4. This area is panicked when you first arrive
1. This place is a spooky environment. 2. A party member is obtained here. 3. Going anywhere but the set path automatically takes you back to the entrance. 4. This place is somewhere to the east of a town.