Since you're so keen on an anti-Code solution, Imma give you one.
We're gonna do exactly ThreePhaseEel's "isolated section of permanent wiring" which is Code correct. With a couple of modifications to cut corners the way you like, and we'll swerve out of our way to violate Code once or twice so you feel like we're saving money. I'll tell you when that happens.
Junction boxes -- $5 + $2/extra box. Put 'em anywhere you want - better to hardwire these boxes than drape extension cords. $1 junction box, I'd mount it within 1" of the floor to remove any issue of wire being unprotected, but at least 3/8" above the floor so the cover plates fit. If it'll be exposed to foot traffic, use a $1 metal Handy-box and metal cover plate. Many boxes have built in cable strain reliefs, if not get a 50 cent cable clamp will do. Insert a 50 cent receptacle and a 20 cent cover plate.
One more box. The perfect location is under the house, yet where the cord that'll be dangling from this box is wholly visible from outside. This is the transition box between house wiring and a flexible power cord that will plug into the generator. This gets a $1 steel Handy-Box with two cable clamps and a 30 cent blank box cover. (I know I'm kinda gold-plating this thing).
Cables -- scrounge or $10-ish. Now, connect all these junction boxes with cable, starting at the funny near-outside box. Just hop from box to box. Leave 7-8" of extra length inside each box. If you only have one box this is super easy.
You know what... I don't really care whether you use NM-B or UF-B.... #14 or #12... or /2 or /3 cable. The upside of NM-B /3 is it's round, so it fills a round hole easily with no air gap, don't use the red wire. I would scrounge/mooch these cables, everybody's got short lengths of NM or UF left over. Hit the Habitat for Humanity store. Whatevs. Don't use extension cord for this.
This is gonna get a 15A plug into a 13A generator so I'm comfortable with using 15A cable (#14). If you expected to plug it into a 20A generator, maybe #12 would worthwhile. Your call.
If you use UF-B, you could take that outside so you actually could fit an inlet for $20+. But I don't see you doing that.
The line cord - scrounge or $7. Now, scrounge around for any appliance cord or roached extension cord that is 14 AWG or larger, and has a good "plug end" for as long as you'll need to get from that Handy-box to a convenient place to either put the generator or an extension cord to the generator. Lop off the socket end if it has one.
Fit this line cord into the handy-box using the other cable clamp. About 7" into the box. This is where we violate Code. We're supposed to fit an inlet to the outside of the building. Draping a cord is naughty, but I'm not sure what we violated. Probably somewhere in 400.8 (allowed use of flexible cords) or 110.12 (pride of workmanship).
Hook it up (45 cents). Inside the near-outside handy-box, splice the 3 wires with wire-nuts (15 cents). You'll be joining solid to stranded wire but that is fine. Put the cover on it. On the receps, hook them up the normal way. Awright, we're done. Light it up.
That said, a generator is the expensive way to power a little bit of electronics. Try a 12V solar system: 2 used golf cart batteries + about 50W solar panel + a MorningStar SunGuard PWM controller, plus appropriate cigarette lighter USB adapters etc. While a great deal more than this, it'd be cheaper than this + fuel.
Man, just buying a gas can in this day and age, what the hey happened to the price of gas cans? And the stupid valves??? That right there makes me mad enough to go solar.