Appreciate your kind words Tom. I am not familiar with the 35-80 lens that was fitted as standard on the Canon at that time, but I suspect that it will not have a very wide aperture, and that may become smaller as you approach the long end of the focal length range maybe f4-f5.6. This keeps the cost down and allows reasonable quality.

You will probably get sharper, more contrasty, photos from a better lens or lenses, but I am pretty sure that it will be OK to begin with. I once exposed a roll of HP5 using a similar Pentax lens, and if used stopped down (f8/f11), it gave perfectly acceptable results. Using a faster film does allow you to use the lens in this way.

For architectural shots the lens may produce some distortion (straight lines appearing curved), while 35mm is not all that wide.

However why not just get out and take photos? If you really catch the bug you will probably want to buy something better, for example a 24-70 f2.8 zoom, or a few fixed focal length lenses, depending upon your budget and what you want to achieve photographically.