Welcome here!

First of all, you have a lot of vars for images. Consider using image lists, like:

CROSS_IMAGE_FILENAME = ['cross.png'] * 8 # or different list
crossImages = [pygame.image.load(filename) for filename in CROSS_IMAGE_FILENAME]

Camera and current position shoud be grouped into Points or something else, so instead of SomethingX and SomethingY you'll have something.x and something.y

mainCharacter is better be named like drawMainCharacter. It is better to use verbs here

Exit == False condition could be written just as not Exit

do you really want to read main character (front).png every loop iteration?

Use lists instead of lots of similarly named variables. Your vars are exactly the reason you have to write such long conditions:

if (keys_pressed[pygame.K_LEFT] and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates8) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates7) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates6) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates5) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates4) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates3) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates2) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates1) and not mainCharacterCoordinatesLeft.colliderect(crossCoordinates) and not mainCharacterCoordinatesLeft.colliderect(leftborder) and not mainCharacterCoordinatesLeft.colliderect(wellCoordinates) and not mainCharacterCoordinatesLeft.colliderect(trainCoordinates) and not mainCharacterCoordinatesLeft.colliderect(graveyardCoordinates)):

where it could be written something like that:

if keys_pressed[pygame.K_LEFT] not any(mainCharacterCoordinatesLeft.colliderect(obj) for obj in objects):

where objects is a list of all in-game objects like trees and houses

all blits should be moved to separate function like drawScene

Welcome here!

First of all, you have a lot of vars for images. Consider using image lists, like:

CROSS_IMAGE_FILENAME = ['cross.png'] * 8 # or different list
crossImages = [pygame.image.load(filename) for filename in CROSS_IMAGE_FILENAME]

Camera and current position should be grouped into Points or something else, so instead of SomethingX and SomethingY you'll have something.x and something.y

mainCharacter is better named something like drawMainCharacter. It is better to use verbs here for function names.

Exit == False condition could be written just as not Exit

do you really want to read main character (front).png every loop iteration?

Use lists instead of lots of similarly named variables. Your vars are exactly the reason you have to write such long conditions:

if (keys_pressed[pygame.K_LEFT] and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates8) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates7) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates6) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates5) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates4) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates3) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates2) and not mainCharacterCoordinatesLeft.colliderect(treeCoordinates1) and not mainCharacterCoordinatesLeft.colliderect(crossCoordinates) and not mainCharacterCoordinatesLeft.colliderect(leftborder) and not mainCharacterCoordinatesLeft.colliderect(wellCoordinates) and not mainCharacterCoordinatesLeft.colliderect(trainCoordinates) and not mainCharacterCoordinatesLeft.colliderect(graveyardCoordinates)):

where it could be written something like that:

if keys_pressed[pygame.K_LEFT] not any(mainCharacterCoordinatesLeft.colliderect(obj) for obj in objects):

where objects is a list of all in-game objects like trees and houses

all blits should be moved to separate function like drawScene