Cream of 3 crops as an extract?

Hey guys I am primarily an extract brewer with ~10 batches under my belt, I am looking to brew the Cream of three crops recipe, but as an extract. I have a few questions.
https://www.homebrewtalk.com/f62/cream-three-crops-cream-ale-66503/

One, would I just steep the corn/rice as I would normal steeping grains? I would use extract for the bulk of my grain bill. I am thinking steeping wouldnt extract the sugars from the adjuncts correctly?

Another option for me is to do a smaller batch such as a 2.5-3 gallon batch on the stove in a BIAB fashion. I have a 5.5 or 6 gallon pot. I have never done an all grain batch before but I've read through the technique and the only extra equipment i would need is a paint strainer bag.

At this point I am leaning towards trying the all grain method, any advice or thoughts are appreciated!

EDIT: My last response didn't make much sense...So I deleted it. I think with your limited equipment you are going to have to reduce the batch size. Rice and Corn need to be mashed... but with so much of each plus some 2 or 6 row to get conversion... you wouldn't likely get any benefit out of making a partial mash... plus replacing all of the 2 row with DME wouldn't get you conversion.

You can do partial, or if you wanted an all extract you could do some math and convert the corn fermentables into a weighted amount of corn sugar and the rice fermentables to a weighted amount of rice syrup. The easiest way to extract would be to omit the rice, just use light dme and add corn sugar.

If you can't do a partial mash (you'd need all of the rice and all of the corn, plus enough two row to convert, so it'd be a fairly large grainbill), you could buy corn sugar and rice syrup solids for the rice and corn.

Sorry if my first post didnt make a whole lot of sense, but I am thinking of doing the whole batch all grain on my stove, but reducing the size to 3 gallons. The original recepie calls for 11.5 gallons, do I just divide all my ingredients by a factor of 3.83?

My stove should have enough oomph to boil the larger volume, (natural gas with 18k BTU)