Theoretically,Technically maybe you might make it without getting more fuel. Is there some reason you must arrive on fumes?

Running out of gas in sight of your destination is still a pain to get a gallon to get you to the station for a fill.

With a drive this long it is safe to assume you might stop to use the toilet or maybe get something to eat. You can add a gallon or two at that time.

With weather like is now you could be faced with an unexpected long detour around an incident. Why add the concern of running out of gas.

You DO NOT need to wait until near empty to add gas.
Using something like gas buddy will show you cheap gas stations along the way you can top off at.
Gas gauges are not that accurate for the last bit in your tank.

A mile in the car is a minute down the road. On foot it can be a lot longer. You also need to walk back.
You will probably make it without getting more gas. The question is why do you want to push it to the limit. Curiosity could leave you in a place not easily able to get a Jerrycan of gas. A Freeway for example.

A detour because of an accident or some other thing could put you miles from an OPEN station.

You might want to get an AAA membership. They would bring you gas if you needed some.

Only you can decide if you want to go to the limits or arrive with some gas in your tank. When on a long drive it is good practise to add gas at the 1/4 tank level.You do not have to FILL it. The next station could be closed when you get there.
In winter weather it is good habit to add when at the 1/2 level. Getting stuck for hours uses up gas to keep warm.

Your actual mileage can be reduced if you use the Air Conditioner, have a lot of stuff in car, have improper tire inflation, dirty filters, stop and go traffic and many other things.

I'm a little confused. Are you talking about keeping the vehicle a consistent speed, or if traffic speed fluctuates?

I'll assume you're talking about your own vehicle, and not other traffic. With some practice, you can keep it at whatever speed you want it to stay at. It might fluctuate a few mph in one direction or another if you're inexperienced or going over unfamiliar terrain, but generally on flattish roads it's possible to maintain a very even speed. It can be tricky to do at first, but if your brand new do your best to stay within 5mph of the speed you want to be going. In the beginning that can be hard enough. As you get better, refine from there.