Please provide some more info:
how long are you going with 2.1.01a?
have you tried a simple shutdonw/restart or (soft-)reset (reset-button and power on again) direct after the installation of PRS+ or after your problem?
are you charging via USB or main-charger?
As said many times before, spontaneous battery drain is also reported for stock-reader, and I personaly use PRS+ 2.1.x from the very first day. Only coming once across this. After reboot, there are no further problems.
About fonts: fonts for epubs, altered by CSS, will work also in 2.0.18, but you will have to open another book and return to the first one, to apply the change.