Whoops, sorry, I didn't notice the other info you requested:
Colors I associate with her are mainly yellow, but also red (usually a soft red), grey, and brown (usually a yellowish brown, like the darker parts of her clothing). Anything of that nature would work, but generally yellow, red, and brown / grey-ish. (If you want to avoid brown or grey, a blue-grey or dark/olive yellow will suffice.)
As for a pattern... I'd say metal, or something else with a solid feel to it. If that's no good, some kind of patch-work pattern would be fitting, too.
I don't know when or if you'll ever draw a psychedelic Hilda, but I appreciate your consideration, and taking the time to read this. All the other ones you've done have been beautiful! Even if you don't do mine, thanks for doing this anyways. Keep up the good work!