There are a lot of little things that matter when it comes to the steering and handling of a Series truck.
Were it me (and it has been over the years) I'd get the front end up on jacks. then wiggle and wobble things - pull and push on the top/bottm of tyres, and left to right. If you feel any movement in the wheels track it back to the source. Slop in both axes can be traced to wheel bearings by having a friend apply the brakes and performing the test again - if the locking of the drum stops it then the bearings are an issue.
If there is still slop, checking the wear in the swivels and adjusting the preload if needed is a good spot to go to. When pulling the wheel left and right put a hand on the track rod ends - they can be a source of flutter in the front end.
Don't forget the arms on both the top and bottom of the steering relay, and the relay itself - worn bushing there can give you no end of wandery steering, as can bad track rods on the steering rod.
Lastly, have a look at the mounts for the steering box and the tightness of the pitman arm on the steering box. I have seen many rovers that drove like pigs because the steering box itself was slopping about - that can be a serious safety issue and isn't always caught by inspection.
Rovers are great vehicles, but there are a lot of moving parts in that front end.
ajr