The tires probably have 50% on them and I'd have to check my pressure.

I have not had the alignment checked. I assumed, perhaps incorrectly, that it wouldn't cause loose / play in the steering or the slight swimming.

 

"Slight swimming" could stem from worn bushes in the panhard rod. Check their condition and replace if necessary. Also, check the condition of radius arm bushes. Same story. If they're worn the truck will feel loose at speed.

 

Ok. I'll get those checked this week. Thank you for some things to look for.