I disagreed with a lot of her rulings, and thought the weird little cult that lefties had built around her over the past decade or so was dumb as hell, but I always liked her personally. She and Scalia were my favorite justices that I had actually met in person.
Trump and McConnell have a few options on what to do; I guarantee they're getting ready to poll-test all of them, since this has the potential to affect the races for president and Senate.
The first option is to do what Democrats want and wait until after the election (either immediately, or until the inauguration, depending on how things play out). This would likely drive up turnout on both sides, and I'm not certain (without any actual data in front of me) who it would benefit more. This would allow Republicans to avoid charges of hypocrisy, however, and could potentially help to shield vulnerable incumbent senators in Arizona, Colorado, Georgia, Iowa, Maine, Montana, and North Carolina.
The second option is to fast-track a nominee and get them confirmed ASAP; if they start moving by the end of next week, choose someone from the original list (i.e. someone who more of the vetting work is already done for), and choose a woman to help avoid fake sexual assault allegations, I think that they could have a new justice sworn in by election day. Once again, I haven't seen any data, but I would be concerned about this energizing the Democratic base relative to the GOP base, especially in the aforementioned states with vulnerable incumbent Republican senators on the ballot. However, this would also help to serve as a check against a President Biden and a Congress completely controlled by Democrats.
The third option is to get the ball rolling now, but don't fast-track it; in other words, go ahead and make a nomination in the next couple of weeks, then have a confirmation around Thanksgiving at the absolute earliest. My gut tells me that this would electorally fall between the other two options in terms of base enthusiasm, probably slightly in Democrats' favor. This also has the electoral problems of the second option, as well as it serving as a sort of insurance against a Democratic trifecta doing something completely stupid.
Regardless, I think we'll know within the next few days what's going to happen.