From what I've been reading, Buford feared the arriving Confederate army would take control of the high ground south of the town so he made steps to slow them down.
My question is, so what if Lee managed to take the high ground? Everything I've read implies that Meade would be forced to attack Lee's army on the high ground and would suffer horrible losses. Why? From my understanding, Richmond was no longer sending Lee men and equipment so if Meade simply encircled the fortified positions and just waited it out Lee's army would eventually just starve to death while the Federal army was still capable of not only getting resupplied, but to acquire more manpower.
We can write a whole book around this and historians, military men and aficionados still debate Gettysburg today, however here are few tips.
There was no reason for Meade to attack Lee if the high ground was lost. During the first day the Federal Army was not concentrated yet and would not make any sense to try to storm the imaginary Confederate Army position being in inferior numbers. Still fighting and Gettysburg was not in Meade's mind even at day 1 of the battle. Meade's original idea was to take position in the so called Pipe Creek line, some 20 miles SE of Gettysburg.
That would have represented a new battle with Meade in the entrenched position and Lee to decide what to do, as Meade's idea was to present this strong line as interposition between Lee's Army of Northern Virginia and Baltimore/Philadelphia. Lee would have been forced, as you point out, to choose between seeking a decisive battle as he tried in Gettysburg or something else lacking a life line to Richmond particularly to resupply ammo.