I think the behavior you describe as "skipping" is rather related to filling small gaps. If it happens after the perimeters and normal infill, this has to be.
A "little loose" X pulley will produce "just" deformed objects or a full mess.
Don't know if the bed of the 2011 kit is similar to what I got early in 2013, but if there is a 3-screws&springs, then I assume it is.
So, what I do is:
- make sure both the hot end and the heated bed are cold; the "paper method" works in such conditions
- move the nozzle 10 mm up, just to prevent any scratches
- move it almost completely to the right, but with the nozzle still above the bed, say, 130 mm
- move the bed to the mid, say, 70 mm
- now home Z repeatedly, and adjust Z endstop, until when pulling the paper you fill some drag (due to vibrations caused by the fan)
- rise nozzle to 10 mm
- move it to 10 mm from the left edge
- home Z and adjust the single screw on the right, trying to obtain the same behavior when pulling the sheet; you have to be sure that this happens after you fix the underside nut.
- check once again on the mid-right; depending on the difference existing at the beginning, you may have altered a bit the setting on the right, by adjusting on the left! No way to avoid one or two itterations.
- when you finished, you have the median of the bed well leveled
- now you take care about tilting back or forth
- check successively the distances in the front and back corners from the right side by homing Z
- adjust both screws on the right, tightening one and loosing the other with the same amount in turn, so that you remove the tilt, if it exists; it is important to use the same amount of turning the screws, since this will maintain the median unchanged.
- when done, if you check on the left side corners, all should be the same; however, if the bed is not flat, then you may have to come to a compromise.
The difficult aspect, but important to be satisfied, is that measurements are relevant only having the underside nuts tight. You have to get used using one hand to action the nut and the other for the screw, obviously using appropriate tools.
While the procedure may appear complicated, it is straightforward and you just have to be patient
Note: It might be the screws are positioned the other way around, with the single screw on the right. Then simply mirror left/right in the procedure.
For PLA, 210C is not necessarily hot. But this depends on the filament (manufacturer, color).