I'd like to know if there is something I can do to close the gap or hide the gap in the blinds. Obviously, I can measure properly and purchase new ones but really trying to avoid that.
I've also thought about curtains, but it's also something I'd like to avoid. Are there any solutions to this?
Here is another photo zoomed out. 
Moving it inward may be the way to go...
Definnetly get those mounts butt up against each other. Depending on what hardware is up in the blind track ( and it looks like the where set right with the adjusters to the outside ) you may be able to take a hack saw and trim the track just slightly like even a 1/16th off each end will end up getting that gap down an 1/8. Etc etc. Or you may be able to find a center style mount for a long single blind set up. And get the two ends in there instead of two end caps. It seems excessive BC there will always be some small gap.