1977 Vigilant

There are actually a few different doors for this model - I think you will find them called "long doors" and "short doors". They are different part numbers.......

Look here to try and ID it.
http://www.discountstove.com/partsvcwbfreestanding.htm#Vigilant

Then search around for the part #

You can also look at woodman's parts plus http://www.woodmanspartsplus.com.

As for the fireback, no more one piece backs available, it is now a two piece. There is a kit that is sold. Is it a significant crack, or is it tight? Normally you see the crack form at the top left corner of the secondary burn chamber. If it is tight, and the back has not warped, you may be able to get away with it a while longer.

Warped doors means it's a short door model. You must disassemble the stove and replace the front and doors together, then get a fireback kit to replace the fireback. Lots of money, but can be done. Go to : grahamthestoveman.com for a front and doors. They're no longer made, but he will have one cause he's awesome. Woodmans has fireback kits, and the kit comes with instructions. Good luck!