I have made several larger size quilts, in fact I used to turn my (uneducated!) nose up at "small quilts, why would anyone do that??"
Now I LOVE minis and table sized pieces and lap quilts as well as bed quilts.
We grow.
Anyway, back to your subject:
The first king I made was the reason I got my first mid-arm quilter. I just could not face quilting it on my domestic.
But lots of people do, and do stunning work.
.

I've done about 6 of these monsters.

This is just how I do it.... no right or wrong intended.

basting steps:
1/ I lay out the backing on a hard flat surface (making sure I have extra backing...... due to my table size that surface becomes my hardwood floor for this size quilt.

2/ I tape (yes that awful word) with blue painter's tape the backing to the floor starting in the middle of each side and working to the corners (added bonus, I can mark the exact center w/ a sharpie on the tape)

3/ Repeat steps 1 and 2 with the batting

4/ I center and lay out the top

5/ I pin the top to the batting and the backing just like I taped the backing and batting down (these will not be permanent, they hold it in place while I pin from the center out) Making sure it is centered and stretched as much as I can

6/ using the curved safety pins (and this is why it's on a hard surface) I pin from the center out to the mid-line on each side. Then I repeat that for each quadrant created until I've pinned with them about 4" apart- I have a TON of safety pins.

7/ untape and I hand baste, yes this takes forever, but I don't have a long arm machine and I'm not sure I could keep everything aligned anyway. I usually baste with a curved needle and leave it laying there where it was taped, I only untape the areas i'm working on so everything stays put.

8/ roll the backing around the batting and pin (using the pins we originally placed on the edges of the top) with raw edges hidden to prevent fraying- with as long as it takes me to quilt these this is important

9/ I remove the pins in about a 12" block starting in the center and working out. Then I quilt that block and move on to the next work out in the same way I pinned


I can usually get a king size quilt basted in a couple hours which means it's under painter's tape for probably just under an hour. I make No claims that this is the "right" way to baste this type of quilt, it's just what works for me! Good luck.