Need help knitting a mock turtle neck

I’m making the “incredible raglan sweater” (with worsted weight wool yarn, gauge 4 st=1") and have finished it all except the neck. I want to do a mock turtle neck, does anyone have any ideas/tricks/advice for how to do it - how to make it look the best?

Thanks - I appreciate any ideas. I’m a new knitter.

My suggestion: pick up stitches around the neck and work in 1x1 or maybe 2x3 ribbing (I think the second is stretchier), without reducing any stitches until it’s the length you like. Then Bind off…

Or, continue until it’s twice the required length, then fold it over and do a 3-needle bind-off at the collar join to the body. That would make a double-thickness, extra warm neck! At the “fold” line you could work a row of Purl to emphasise the edge, or be fancy and use a Picot (perhaps not on a mock-turtleneck though)