I have a crosman DPMS A4 "AR15" air rifle that has the long crappy trigger.
Is it a big deal to fix the trigger in this air rifle?
It  looks like the whole thing has to be opened up to remove the "gun" part to ajust/fix the trigger.
I have watched some of the remove spring and add ball bearing fix on youtube, looks easy to do but this is in a clam shell around it so many more screws.
Is there anything I should know to look out for?
Or a better way to get the trigger out?

Did the trigger job, lots of screws, no need to remove sights nor remove screws on front sight mount.
Added the 9x5x3mm bearing and removed the trigger adjustment screw.
Very easy, other than all the screws to open up the shell.
It made a good trigger out of a long gritty is ever going to go off? Trigger.