By Phil Mattingly, CNN

(CNN) -- Things are just about wrapped up (allegedly) on a massive spending deal, according to several aides working on the process.

Republicans and Democrats were still trading proposals late into Tuesday night, according to sources, trying to hammer out the final details on an array of thorny issues, from border security funding and the ongoing battle over funding for the Gateway Tunnel project, to a fix for the 2017 tax law and whether to include any school safety provisions in the bill at all.

Bottom line: Aides say to expect the bill to be filed around noon Wednesday.

The expectation is it will take until Saturday to move it through the House and Senate, and lawmakers will likely need a 24-hour or so continuing resolution to temporarily fund the government at existing levels to bridge them to that point -- though things can always move faster if lawmakers just want to leave town and are willing to agree to skip chamber protocols that require more time.

The mood on the Hill: Not great!

What about the weather: The House and Senate are planning to work Wednesday. There are no snow days when there's a funding deadline.

So when is this all going to happen: As of now, the House will likely vote Friday. The Senate will then move on the bill as quickly as the chamber's members will allow.

Technically, if all present senators agree, the Senate could move it quickly. But that's unlikely at the moment, leaving a short-term continuing resolution as the path to finish everything up without an ever-embarrassing third shutdown.

Who to watch: Sen. Rand Paul, whose objections to the deal that set the path for this omnibus - and leadership's refusal to give him an amendment vote -- led to the last shutdown. The Kentucky Republican told CNN's Ted Barrett and Lauren Fox he was clearly opposed to the bill but hadn't decided if he was going to drag out the process again.

Important note: Right now, aides don't want to talk about a continuing resolution. They want everyone focused on getting everything wrapped up as quickly as possible. The White House however did not mind bringing it up.

Reminder: A two-week recess begins Saturday. And so does the march on gun violence in Washington -- something many lawmakers would rather not be in town for at this point.

If needed, are the votes there for a short-term continuing resolution: Shouldn't be a problem, aides say. "We all know how this is going to end," one said. "Do you want the 'idiots create another shutdown' headlines or not?"

And are the votes there for the final omnibus bill: Yes, according to everyone involved. This is a "when" not "if" situation when it comes to passage.

The final hurdles

The border wall: The White House wanted multi-year funding for border security (i.e.: the wall). Democrats were willing to potentially do that in exchange for a pathway to citizenship for the eligible population of recipients for the Deferred Action for Childhood Arrivals program. That blew up (and came back to life, and blew up again, and so on), narrowing the negotiation to border funding for a single year. That number would be the $1.6 billion the White House requested, but haggling over the type of structure -- and where the structure could be placed -- has slowed the talks down. Democrats have also attempted to link smaller bore immigration priorities to the border money.

The Gateway Tunnel Project: The President's opposition -- and verbal veto threat to GOP leaders -- is no secret, so much of the negotiations have centered on finding a way to draft the language that doesn't explicitly kill funding for the project, but leaves it to the discretion of the transportation secretary. Distinction without a difference? Maybe. But that's likely the best supporters could get at this stage.

The Grain Glitch: Long an issue in the negotiations, Republicans have been trying to secure a fix in the 2017 tax law that allows a break for farmers that sell grain to co-ops. Democrats have been willing to address the issue — so long as they get something in return, in this case a bump in affordable housing credits. That exchange has remained a sticking point.

Guns: The measure to incentivize reporting to a national criminal database known as Fix NICS and a separate school safety bill have remained in the conversations for days, but the split over Republicans, who want to include the bipartisan measure, and Democrats, who want to hold them out for a broader gun violence in the weeks ahead, was still complicating things Tuesday night.