The result is a very comfortable Donmar Warehouse-style 200-seater theatre (black tip-up banquettes, an extraordinarily roomy-looking lighting box, a very high ceiling), an adjacent 90-seater studio, an education/rehearsal/reception room, full of light and airiness, three decent-sized dressing rooms, showers, two bars (one of them doubling as an all-day coffee shop at ground level with the box office), a hundred local volunteeers, just four permanent staff, a £12 Tuesday for all local residents (in the N4 post-code), offices, skylights, an atrium, passing buses, a boisterous boozer (full of Arsenal fans) on the corner.
As the song goes, I couldn't have liked it more. Of course, what the work itself will be like remains to be seen. The opener - reviews should start appearing tomorrow - is a perfectly decent five year-old American play, These Shining Lives, about female watch-makers in Chicago in the 1920s affected by the radium they were exposed to in painting the dials.
The reception at last night's preview for sponsors, friends and local supporters, was appropriately enthusiastic. Just to have this marvellous place up and running was enough for them, as indeed it almost was for me.
Jez Bond spoke a few words of welcome, accompanied onto the stage by his ever-present mutt, Hazel, a big floppy honeycomb-coloured mastiff he adopted from the Battersea Dogs Home. No surprise to learn, then, that Jez went to Oundle School, where that other well-known dog-lover, Christopher Richardson, was the teacher who started the new theatre there before moving on to found the Pleasance.
Like Richardson, Jez oozes Oundle old school charm, and he strikes a similarly imposing figure, gliding round the Park in a smartly cut suit with shiny lapels (not quite a tux) and a trendily informal shirt. "Knowing you've done something to the best of your ability of which you're proud is what matters," he said, reading from notes on his i-phone, "it's been a long journey of four years; welcome to the first stage of the adventure."
So, how has he done it? The old building and the site - a blacksmiths and stables in the mid 19th century; that explains the authentic, lived-in feel of the place - cost £2.5m. He sold on two floors at the top to be converted into flats and made back £1m. The other £1.5m he has raised through sponsorship, donations and charitable trusts.
Cleverly, too, the project is part of a larger regeneration programme in the area, including the expansion of the John Jones Arts Building right across the road; John Jones specialise in picture frames, and will sponsor the first exhibition to adorn the brick walls in the comfortably wide corridors around the building.
In the cafe upstairs, a forest of theatre books hangs discreetly from the ceiling, while the bar itself is tastefully plastered in theatre flyers and programmes. There's a perfectly okay house wine, some splendid posh bottled beers and a canteen service that hasn't got going yet; only filo pastries were available last night, and packets of smart crisps.
But my companion, local resident Jen Payne, who has worked in all aspects of theatre - onstage, backstage and front-of-house - has already marked her card and will be going back fairly soon, she says.
The project seems to have caught on in the profession generally, with all sorts of affidavits flying around from Ian McKellen, Nicholas Hytner, Alison Steadman, Mike Leigh and Maureen Lipman (who is slated to appear there in July in a new play, Daytona, by actor Oliver Cotton, currently appearing in Passion Play).
You sense a momentum, a lot of good will, and a mood of fun and adventure. The Park Theatre is less high-end in the market than the Donmar, less glitzy than the Almeida, but has something of both those places, with a particular atmosphere of its own. I think I'm looking forward to going there regularly, too. And the top price ticket is £19.50.