When I mount my external usb-drive within KDE it’s mounted on /media/disk.
When I mount my external usb-drive (yes, the same one) within LXDE it’s mounted on /media/72F580136411D534.
Not a great deal, but when I use DirSyncPro to backup some stuff I have to make adjustments to my saved settings, e.g. change the target folders.
I know you can configure this in Systemsettings for KDE. I believe you straight away, but there is a cure for it:
label the partition(s) on the disk. Let’s say /dev/sdx6 contains the backup, then label that one as ‘Backup’. It will mount in /media/Backup, AFAIK on both KDE and LXDE
There might as well be an option for LXDE on how to mount external media.