Hi
The time taken to render your film depends to a great extent on the speed of your PC. as well as the number and duration of the files used in the video and the manipulation made for each clip.
I have just completed a Looooong holiday film originally recorded as 400+ clips of MPEG4 video but converted to MPEG2 for rough editing in VP. This project after initial assembly was 1hr 45 mins in length. As I needed to keep a copy of this for future editing and the family wanted all the original footage ...nicely edited of course..it had to be saved as an avi HD 720. This took ALL NIGHT to render...about 10 hours. During the process the window showed a remaining time of 2 hours. But I think this based on the percentage done and the time taken to do that...what remains to be done can't be properly estimated it seems hence the inaccurate duration shown. Still, it got there.
I always save an avi first in case of accidents.
Saving to a DVD (RW) didn't get very far as VP found an error writing to the disc. 
Anyway I normally write to DVD with windows DVD maker which works OK but this also took several hours. 
I think one must just be patient.
Nat