The Dems main pathway to victory remains sweeping the Blue wall in the Rust Belt (there are other theoretical pathways but they are pretty unlikely). PA is semi-diverse, while MI and WI have a substantial white majority. These are the voters that will again decide the Electoral College, unless something weird happens.
High base turnout is always great but it won't matter if you run up the score in the "national popular vote," unless those votes show up in just the right places. Overall I think we're in agreement on the contours of the election; I do think a VP who appeals to Midwestern white voters will be important. There are various ways to get to 270 EC, but most current models suggest Dems can't afford to lose any of the above 3 states.
2016 showed that the Blue Wall, if it exists, only includes Illinois and Minnesota in the Midwest. Ohio is a goner until they unfuck their gerrymandering, and Michigan/Wisconsin is anyone's guess. I'd count them as swing states. Pennsylvania isn't really Midwest, although I'd consider Pennsylvania a swing state too.
That said, Michigan, Wisconsin and Pennsylvania are probably must-wins...i.e. bellwether states that if they all go for a candidate, that candidate probably wins the whole thing. Split them up and who knows. A lot of people still sleep on a 269-269 EC tie where it goes to the House, which means it goes to Republicans.
For me, the most important things that Democrats should be working on:
1. Getting every Democrat who votes Democrat to the polls. Cut the political ad budget by 95% around September (they've all been ignored by that time anyway) and focus on getting people information about early voting (the best voting), absentee voting, mail-in voting, and in-person voting...and get them a fucking ride to their polling location.
2. Get the god damn young people who almost always as a majority or almost-majority stay home, to vote. Sure, there's fascist enablers and collaborators at all ages, but young people who still have optimism need to have that optimism championed by a candidate. I don't think these optimism issues are too difficult to parse out: abortion, marijuana, affordable housing/schooling, and jobs Also, make sure 1. above is applied to them, too. They all don't live in cities with great public transportation.
Don't get me started on the popular vote. It's a relatively pointless stat except as a review of how each state vote turned out. I've said it multiple times, 500,000,000 Californians can't elect the President. It's also the reason why national polling data is useless if it isn't divided by states, because who cares, again, if Harris wins every single Californian vote - Harris only needs 50.01% of them to win all of California's Electoral College votes.
The VP pick should be someone who isn't going to piss off edgy Democratic voters, and isn't going to spook "Independents", independents, "centrists", and Never-Trumpers. Which is why no one in the Democratic Party should say the fucking word gun over the next 4 months, for fucks sake, holy shit, why do I even have to point that out, oh my god.
I was sounding the alert back in 2020 that Biden barely beat Trump regardless of the EC vote totals. 43,000 people in 3 states gave Biden the win. Had Trump been even remotely not-dogshit during COVID, he'd have won re-election. Between dead COVID people and freaked out normal people, that 43,000 votes over 3 states was essentially a rounding error.
Get your people to vote. Get never-voters to vote. That's how you win an election, especially against a pseudo-populist right-wing authoritarian like Trump.
Luckily J.D. "Couch-Cushions" Vance isn't likely to help pick up very many more voters.