My toilet has been bubbling when a large amount of water is drained from any one or numerous fixtures in the bathroom. If I'm running the shower there are no problems, If I'm just washing my hands there is no problem. However, If I fill the tub for 10-20 seconds and then drain the water all at once the toilet goes bonkers.

Also my kitchen sink has been gurgling after a large amount of water is drained from it. Although this problem seems to come and go. It currently isn't behaving this way, but who knows; Tomorrow is a new day! :(

I tried flushing the roof vents with a garden hose a week ago as well as taking my 25' hand auger to them, and my kitchen vent backup up to the roof, and when I flushed the vent for my bathroom there was water in my basement around where the vent is.(I'm assuming that's an unrelated but generally bad sign.)

March of 2009 I had a section of my lateral replaced because it collapsed/roots. I had Roto-Rooter come out and $2,000 later the problem was fixed. Before they came out I was having all of these same problems, except one difference. The difference being before if I would run my clothes washer, which is located in the basement, and it was draining the water would backup into the basement where the washer tries to drain. That hasn't happened yet, and I've tried to make it do it by running the washer on the 'extra large' load setting to get the most amount of water to drain each cycle.

I am extremely confused, and to summarize here is why:

1. The kitchen vent backing up is clearly a problem, but why would that cause the bathroom issues? The kitchen is 'before' the bathroom in the plumbing scheme of things in my house. What can I do about the kitchen vent being clogged? I haven't checked it in a week but if it won't flush with a garden hose, and my 25' snake didn't catch anything what should I do?

2. Why is it only when a large amount of water is drained at once? I can run the shower for 20 minutes, and then let the tub fill for 10-20 seconds, and as soon as I drain that the toilet bubbles. I can come home 8 hours of work when no water was run in the house at all and fill either the tub or bathroom sink for 10-20 seconds, and as soon as I drain that the toilet bubbles.

Any insights at all or am I to the point where I should basically call a plumber?

It sounds like a simple partial blockage past the bathroom, maybe roots and collapse again. Like you said, tubs, toilets, full sinks and washers dump a lot more water at once than showers and basins. Hire a company that has a fiber optic camera. Identify the trees in your yard! Any willow or sumac (but any tree can do this)? Cut them down if they are too close anyway.
If your waste pipes and vents are cast iron, the walls can get thin and rust out, or is there a connection to PVC with a clamp that could be loose, etc. I wouldn't worry too much about the water from flushing the vent if that's the only time it happens, and you can't see what's in the walls and roof, and you don't smell odors in general from sewer gases.
I'm not a plumber just a homeowner!

You have two problems.

The kitchen vent pipe is blocked. A blocked vent pipe will cause a gurgling sound when a large amount of water goes down the drain. If the vent were not blocked you would not have been able to fill the vent pipe with water. All the water would have simple have gone down the sewer. The blockage is above the kitchen sink or the water would have come out the sink.
Snake the vent with a power snake.

You have a partial blockage in the drain the serves the bathroom. It will soon be a complete blockage. This blockage is probably between the toilet and the main stack or in the main stack.

Pull the toilet and snake the line.

I worked on the bathroom some more after making my post. I tried to snake it out from the sink (because I was uncomfortable removing the toilet). I didn't have much success with that, but then I filled and drained the tub and plunged like mad against the bubbles. That seems to have done the trick, at least for now.

Once it's done raining here I'll get back on the roof and work on the kitchen vent some more.

Thanks!

Congratulations on the bath. Remember, when using a plunger you must always block the overflow. When plunging a sink you can usually just plug the overflow with your finger. When plunging a tub remove the overflow cover plate and plug with a wet cloth. Or just tape it up with duct tape.