I see from having a look at Sketchup that it is possible to export to Blender or 3Ds Max if you have one or other, however, to do that you would need the full program otherwise export is locked and at $695 a little expensive I think for most of us. So it is not possible, at least for me anyway, to test the theory I put across about using a model as a template although western indicates that might be the best way.
Only way for me would be to use drawings with some dimensions on and with the usual views needed for any model, top, side and front and you would have to find that information. The only other way would be to try freehand from the images you show but again some idea of size would be necessary to make at least a box as a guide and to be honest might not produce good results as some parts could be out of scale.
Also, at least some good photographs to use as textures but they would need to be views aligned to at least front and both sides and not angled or twisted in anyway, maybe you have a church near you to find those type of references.
So sorry without any good information I cannot help.
Wishing you all the very best, Pete.
