Is there a mod or setting I can use to be able to zoom closer while on horseback? The default minimum is way too far back for my preference. Thanks in advance!

Probably not, that ability was removed in patch 1.6 which added mounted combat, see the description for this mod

http://www.nexusmods.com/skyrim/mods/37347/?

Not sure if someone has resolved this, as this mod is also broken

http://www.nexusmods.com/skyrim/mods/10623/?