Help with Yarn Substitution

I’m just getting into sweater knitting (working on my second one after a well-received first!) and with my youngest nephew’s 2nd birthday party coming up Nov 16, I decided it would be great to knit him a sweater. He likes carrying things around all the time, so when I saw this pattern, I knew it would be a great one for him. Now for my question…

The pattern calls for a yarn that’s been discontinued and I haven’t been able to find a similar BULKY weight yarn that I like for this. I’ve knit with yarn doubled up, so I thought that might be a good way of going. My question is what weight should the yarn be? I was thinking probably Sport or Worsted but I wanted to ask before I make any purchases. Also, how many yards would I need? Thanks for taking time out to look at my question :slight_smile:

Edit: I saw this yarn and thought it was really cute. Think it would work?

Probably sport or dk, I think worsted would be too thick. Especially knit on size 7 and 9! The crayon should work up well doubled, you’d probably need twice as much as the pattern calls for.