I debated whether to post this or not... Ultimately, if you like the original ending, please stop here. If you crave a happier finale... read on.
"I think Murdock is staying locked up for good this time." Gwen told herself, and an impossibly distant Miles Morales. "I'll never get over the fact that he's a hero on your Earth..."
She absently plucked at the webbing she was suspended in, above their familiar meeting place. Finding that she could never wait for their annual redezvous to talk to him, and since he couldn't respond anyhow, Gwen made the trip to their vantage point more regularly than the once a year they'd agreed on. In the half a decade since her promise, she'd been to that intersection dozens of times. It had only been two weeks since the last time she'd scaled the sky scrapers to have her routinely one-sided conversation.
Anyway, locking up my New York's Kingpin got me thinking about yours... I wonder..." She bit her lip, and sighed. "I guess I wonder a lot."
The sun touched the horizon, and Gwen watched as it dipped lower, and lower. As it fell, it painted the sky over the park in rich and vivid tones of scarlet and burgundy. The wind played with her exposed hair, and her loose hood. A tear rolled down her cheek and she cursed under her breath, rolling her eyes and brushing it away frustratedly.
"I shouldn't be so optimistic about Murdock. It's childish. Stupid." She spat the word. "He'll just run the streets from in prison by proxy. He'll be just as—" Gwen stopped. An idea was taking shape. "Proxy." She whispered the word.
Before the plan was solid Gwen was opening a portal to Earth-928; she needed to talk to Miguel. She didn't want to visualize it clearly in her mind before she could get his opinion. She didn't dare get her hopes up...
She contacted this dimension's Spider-man, and swung through the distopian streets of 2099's Nueva York as fast as spiderly possible to meet up with him.
The roof they ran into each other on was spacious, cement, and not unlike the rooftops of her New York, save the excessive number of satellite dishes, radio antennae, and other transmitters/receivers she couldn't guess at the function of. Gwen was breathless, she skipped pleasantries and proper greetings, explaining her idea between deep breaths:
Instead of traveling back and forth directly between dimensions A and B, one could take a random route through three or more dimensions, acting like proxy servers for traveling data. A different path every time—theoretically—without weakening the bond directly between the two dimensions in question...
Miguel listened silently. If his mask hasn't obscured it, Gwen would have seen the genuine excitement his expression conveyed.
He took her back to his lab, and over the following twenty-odd consecutive hours, Gwen Stacy and Miguel O'Hara developed new programming for their inter-dimensional portal devices. Along with a minor hardware overhaul that would allow for multiple portals to open simultaneously, their new programming would select a random sequence of dimensions ending with your specific destination, and open a series of portals through each one. The effect, once complete, was an effective short hallway of windows into other worlds; if you've ever faced two mirrors to one another, you'll have an idea of this passageway's appearance.
The first time she opened the chain of portals Gwen was agog, between each of the windows a glimpse of another universe was visible, all so similar but none identical. Gwen walked through. She found she had to be careful with her step, in one of the dimensions, the rooftop that was consistent to all the others was simply gone. However, the portals were close enough together that she could simply step through that world, without ever actually setting foot in it.
At the end of the hallway-of-portals, Gwen inhaled the air of Earth-1610 for the first time in over five years. It was both familiar and alien.
She took several deep breaths, unable to believe her eyes, ears, and nose, before receiving a jolt to the sense she trusted most.
Gwen snapped around a hundred and eighty degrees, webslingers primed and aimed, neck hairs erect.
There he was, impossibly, beaming his smile that she'd missed more than anything. He became blurry as her vision filled with tears. It felt like a dream. His hand braced her shoulder, "Hey."