My question is what can I do to cut down the reverb in the room and get that nice clean Hollywood sound?
You're not likely to get all the way there --- but you've taken the first step which is to be concerned with the sound. The best would be to somehow get an experienced location sound person on your crew -- but if that is not possible two things: 1) get sound takes of the ambient sound of the train station. Presence. The idea is to have this to fill the track between the dialogue or to mix with it in post. You have a shot to control this sound and get the station sounding like you want it to. 2) Get sound takes of just the dialogue with mics in close. By this I mean have your actors redo their lines just for the sake of a clean, tightly mic'd sound take. For example if the lav mic is doing the best but you only have one, trade the mic around so all the actors have given their lines using the lav. This can be done relatively quickly as it is sound only. Mixed with the "presence" track this could do wonders. This is "no budget" ADR.

3) Record each mic to a separate track if possible so you can mute unused sounds later if needed.

--Ethan

xberk's advice is best, I think. Get the ambient sounds, preferably scene length or longer - and preferably with a quality sound recorder (Zoom H4?). Then get the dialog during the scenes/setups for reference and rhythms. Have the talent loop the dialog back in the studio (or your garage or basement with blankets). Add ambient sounds after that. I have done this to very good effect.

Note: if there are different setups in the scene the ambient sounds might change - you might consider recording an "ambient set" of sounds to draw from.

" there are times when all four mics need to be open for the four actors to interact."

How close are those actors?

As Ethan says above your only chance at this is to record each mic into its own channel however even then if the actors are close and talking at the same time you can have problems.

Expecting anyone to twidle 4 knobs fast enough to catch the end of one actors line and the start of a another is a huge ask. A 4 channel recorder solves that problem.
The next problem is having two mics recording what is almost the same sound source. The delay as sound travels through the air means that when the two tracks are mixed you can some frequencies cancelling and some adding i.e. combing. You can correct this in post using a delay FX or possibly just by inverting the phase. In general if the distance between the mics is greater than 3 times the distance from each mic to its sound source you can ignore this problem.

I have to say a lot of no budget productions do fail because of audio problems. There's zillions of words and bitter debates over "which camera...". If only as much energy went into "Which mic..." or even just getting any mic in the right place. <sigh>

ADR is very easy to do using Vegas. It is time consumming and demanding of the talent. Do NOT let them leave an ADR session until you've checked it carefully against vision and intercut with the ajoining scenes. Sudden shifts in tone, cadence or any of the other things that we use to recognise speech is a problem.

One last tip. Don't just record lots of ambient, also record an impulse, a clapper could be enough. Then you can use Acoustic Mirror to match the sound to the shot. Just as the camera moves the viewer close or far from the actor the sound should match.

Bob.

xberk's on target.

Record the dialog separately in a controlled environment and add/mix in post just like the film world has done for years!

Thank you all for your suggestions, my head is spinning. I don't have a 4 channel recorder and I'll only have these actors for one day. Even if they did record a desperate dialog tracks, I don't think it could be lip synced. There is only one case where two actors are speaking very near each other and I used only one mic so as not to break the 3 to 1 rule.

I think if I do less wide shots with multiple mics, and where possible place the mic in the sound box as close to the actors as possible I may be alright. I think the whole thing just got out of hand and I didn't realize I had a problem until after the fact. Now, I'm focused.

Have the talent loop the dialog back in the studio (or your garage or basement with blankets).

I agree. This is a better way -- BUT -- will it happen? .. Get it while you can on the day of shooting and get it later too with more control if you can. In "no budget land" actors have a way of disappointing you.

I don't think it could be lip synced.
Maybe not perfectly -- no ADR is ever perfect. But it's like horseshoes -- close counts.