@Syrinx the closest I can find is the Fiona sundress from Closet Core (Closet Case).

Generally the best stretch stitch options on a lock stitch machine are the two-forward-one-back stitch (02 in the attached image) or the 'lightening' stitch which looks a bit like a long line of number 7s (03 in the image).  If you need to topstitch use the triple zig-zag (05) or straight stitch with a twin needle.

What ever you choose you'll need to experiment a bit to get the tensions and presser foot controls right.

I know that @UttaRetch will disagree  but if you are serious about sewing a lot of knit fabrics investing in an overlocker really is something to consider.

Hi Pete
These works of art did not happen just by cuffing it
No they didn't!  Three of them are from written instructions in Books.
The firt image of the quilt on the bed in claret/wine/rose/burgandy colours is 'Shakespear in the Park' from Judy Martin's The Creative Pattern Book
The little XOX quilt (Sisters Log Cabin)and the blue/green/rust bed quilt (Buckeye Log Cabin) came from  her book Extraordinary Log Cabin Quilts.
See also her website:  http://www.judymartin.com/
She gives very detailed instructions for the sizes to cut and instructions for putting it all together, but they aren't beginners stuff!

The Blue Lucky Stars quilt was just made up as I went along.
It was a friendship block swap way back in the days of the predecessor to The Sewing Place, though most of the participants are here on TSP: @Ellabella @Efemera @Iminei @QuiltySisty @Sheilago @Sakar @Lowena myself and Fabric Floosie each made nine blocks, one for ourselves and one for each of the others.  I requested blues and purples and I put them together with pieced 'sashing' which creates a lot more stars. When my selection arrived I found that one of the purples was close to bright pink and a couple of the blues were cyan blue as well as the darker blues and purples, so I went through stash and found a similar bright pink and cyan blue to make it all go together.  Then I just made up the corners and borders and finished it with prairie point edges.  I know whoeach of the blocks came from because I put my own block in the centre and embroidered the other names onto it closest to where their block is.

Went to the fabric shop today and they have massive options for quilting.
Rolls and rolls of it all different patterns.
My advice is to keep to small scale prints and blender fabrics and best if only a couple of colours in each fabric.  That way you have more control over how you place the colours.  For backing fabric, or if I'm using just one white for the lights, I do buy bigger pieces of fabric, but 4 fat quarters should be the same price as a full metre.

So by " Piecing" this means sewing up a square block of lots of pieces to create a square?  By machine?
Piecing is the patchwork - sewing the small pieces of fabric together.

My sister in law laid segments ( for the block?)  On card and then hand stitched them!
Sounds like English Paper piecing (EPP) mostly used with hexagons and diamonds.
Or it might have been Foundation Paper piecing (FPP) used for irregular and complex shapes.

Patchwork with machine piecing uses mostly squares, rectangles and triangles cut from squares.  The pieces are sewn together to make blocks (which are usually square) and then the blocks are sewn together to make a quilt top.  It's just a
logical way of putting things together.

What parts of a quilt requires hand stitching?
Any of it, none of it or a combination.  Your choice.

Can I machine a whole quilt?
Yes!
Sewing the small pieces into blocks and joining the blocks together is straightforward (though it takes a bit of practice to get points coming together nicely).  Quilting is a bit more difficult, especially if you are trying to get a large quilt crammed into the harp space.  On my big wine/rose/burgandy/claret quilt I chose to hand quilt it.  The other bed quilt I used a "quilt as you go" technique whereby the blocks were joined into strips, a strip was quilted, then a second strip quilted and joined to the first one, then another strip quilted and joined on to the previous pair and so one.  Other QAYG methods have a strip of sashing between the strips (and usually between the blocks in each strip) but that definitely wasn't an option for that design.

ETA:  AS the others have said, start with something small, not a full size bed quilt!

I have read that quilters love the Singer 221.
That means that a quilt can be made with a straight stitcher?....
Hooray I can use my 201?
How do they feed a massive quilt through such a small harp on the 221?
I need to make a single quilt.

A 221 is fine for piecing, or quilt as you go but you WON'T get a full size bed quilt through a 221.
As you've got a 201 use that - even so it's quite a challenge to get even a single bed size quilt under the harp.

@Efemera I think this is the first "P" machine I've seen. I'm wondering if the flat top is unique to the P model.

My Aluminium body 201K has a flat top. I think it might just be the Aussie sunshine which makes it show up more.
As you can see I just shove the same Gütermann spool onto the regular spool pin and it's not a problem but if I want to use a cone or a bi-cone I do use a thread stand behind the machine. 
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That join looks pretty good to me.

I concur with @toileandtrouble 's suggestion of a narrow piece on each side - and try to get the join running down the tree trunks.