howdo,
if you want to go this route, check the tension of the belt.
twist the belt where the upper arrow is, The turn water pump (WP) by bare hand.
If WP doesn't turn, then TB is too tight, if it turns very freely - too loose.
I think that it'll be too much to ask of you to alight all timing marks in field and see how they align. The current owner may not like this "invasion" and may not allow you to "tinker" with timing marks.
The picture:
There's also a pre-purchase inspection guidelines posted somewhere on this forum - they may be useful.
I didn't do all these precautionary steps, I just started it up, drove it on the trailer...