Well, 1990 Virginia and S. Carolina were pre-tech boom, though Virginia still has a lot of know-how for satellite communication, having a bunch of assets of the
Contel corporation, and Virginia was their HQ for satellite telecom IIRC*. And while the Federal Halo is smaller in Virginia in 1990 than it is now, a lot of the premier telecom and military corporations were set up in Virginia at the time, plus Virginia has all the infrastructure for running the US Military (Pentagon) and CIA (Langley), as well as the largest shipyards in the world (Newport News) which is capable of building both nuclear aircraft carriers and submarines. This means that from a technical side, Virginia actually has a LOT of basic know-how for modern technology, and bear in mind that while Silicon Valley gets a lot of the credit for the ideas of the tech boom, the early internet's core infrastructure was mainly built in Virginia built out from computer networks for the Federal government that get ISOT with them, so while there will be delays, some sort of Internet will still be developed.
Virginia also has natural uranium reserves and massive coal reserves, so it should be good for electrical power for the foreseeable future even without the infusion of the ISOT extra resources.
The geographic proximity of Virginia and S. Carolina mean they likely will work together. Virginia's governor at the time is
Douglas Wilder**, a moderate Democrat, while S. Carolina's is
Carroll Campbell, a moderate Republican. There's an easy sea route between the two states as well as the
Intracoastal Waterway.
The big issue for both States is going to be Oil. This is obviously where Texas comes in, and sea trade will be the primary means for both to get oil. Texas also has considerable technical know-how, being the home for the
Texas Instruments, which manufacture semiconductors and other computer hardware.
Frankly, the odd one out here is Wisconsin. The other US states can all trade and support each other via sea, all have well developed seaports for it, and thus while Texas probably goes its own way as an independent nation, Virginia and S.Carolina probably look at some form of unified government after a time. Wisconsin, on the other hand, has no easy trade routes with anyone. They have some degree of natural wealth, but lack a lot of the institutional knowledge that other states have. Politically they're also the odd duck out, with 1990s Virginia, S.Carolina, and Texas all being very Conservative states. I suspect this means they'll take a different track compared to the coastal states, likely one that is built on uplifting Native American tribes and downteching to some sustainable level, as building up the infrastructure necessary to reconnect to the other states is a massive long term project that might even take longer than their spare resources give them.
Meanwhile the Coastal states will seek to maintain their technological level as much as possible, with long term plans to ensure their ability to secure the resources needed. Virginia is the undisputed master of the oceans in this scenario, given it's ability to build modern warships and holding of the largest military shipyards in the world (no, not just in the ISOT, I mean modern world... Newport News is BIG). There will likely build overland routes between Virginia and S.Carolina over time too, with the region that was N.Carolina likely resettled over time by people moving south from Virginia and North from S.Carolina. I can also see them expanding in the regions of Maryland, Pennsylvania, and West Virginia. Pennsylvania especially so that the Virginia/Carolina Collective can gain their own domestic oil production. Likewise you'd like see them expand some south into what was Georgia. Expanding west across the Appalachians will take longer, as building the necessary passes for modern transit will take a long time and there's little demand for it initially.
You likely will see a more moderate approach to dealing with the Native Americans from these states too, likely trying to work with them as much as possible. We really don't have a good idea what 1500s N.America looked like from the Native Perspective, as this was before the massive smallpox epidemic really hit them IIRC. In fact, one of the major efforts that would be undertaken by those states would be smallpox vaccines for EVERYONE ASAP, starting with their own citizens and then spreading out to whatever local tribes they have managed to befriend.
-----------------------
* How does one even know this? My father worked for Contel, in their satellite and government contracting division, in Virginia, in the late 1980s... which does mean that this one has been ISOT per OP...
** I know this sounds bizarre, but he really is. Wilder is still alive and has been very critical of the Democrat Party of Virginia to the point where he's flirted with endorsing Republicans and even was a part of the present Republican Governor's transition team.