That looks a nice truck, and a nice low mileage too.
One word of caution about rust treatment - IME, and if you intend keeping it, do NOT underseal it - it holds the water and/or salt against the panels and creates a perfect environment for corrosion to eat the vehicle alive.
Plenty of threads on here about what to do about surface rust like on the chassis, but in a nutshell:-
That level of surface rust is borderline irrelevant.
So, As
@Wimblowdriver said above, make sure the chassis is clean inside, and that all the drain holes are clear too, and then use a proper cavity wax to arrest the internal corrosion - something like Bilt hamber Dynax S50, or one of the Dinitrol range - again, a search on here will tell you lots...... ( even that I used to swear by Waxoyl, but now use Bilt Hamber, as the price is essentially the same, but the product is, IMHO, infinitely superior ). remember that the rust you can't see will be a lot worse than that you can see, and treat the chassis to better internal protection - IME, 99.9% of the time, they will rust from the inside out......
I would then treat the surface rust on the chassis with either Bilt Hambers De-Oxy gel, or Fertan. I use fertan, which can be applied with a garden sprayer, and painted more or less at your leisure. It also uses water against the rust, and I like the irony. Then treat with your choice of wax protection - the bilt hamber site is really useful, and they are helpful if you want some person to person technical advice too.....
In terms of the heavy clutch and brakes.... you can test the brake servo by applying the brakes (repeatedly) with the engine off to run the servo out of vacuum ( until the they are next to impossible to apply ) - then start the engine and simultaneously apply weight to the pedal - which should descend as the pump evacuates the servo chamber.....
The clutch will be heavy - ( you could possibly compare it to another 'fender, if the dealers have one... ), it can be tweaked by changing the spring in the pedal assembly, or servo assisted using something like the red booster kit, which is quite expensive, (£400 for the parts) or a remote servo, which can be bought off flea bay for less than £100....
I'm in the process of servo assisting SWMBO's clutch, and when I have done it, I'll post the details up.... but there's a thread on difflock:-
forum.difflock.com/viewtopic.php?t=52395&sid=731f953ed68cab38df960c7de03954a4
which should explain it well enough...
Best of luck with it...
