A lot of that era will be similar enough that you can fudge it with modern equipment like JR's. The biggest difference would be the logos and brands on their trailers and containers since they are more recent than what you would see in the early 90s. If you don't mind that, or you feel like reskinning to era appropriate logos, that is your best bet. You would also see some holdovers from the 80s like 45' trailers and maybe a few lingering 40', but these will become rarer the further you push into the 90s. Both of these can be obtained for free from RRmods. For rolling stock you can use the 89' TOFC cars from SoCal Trains or JR. Just remember that Trailer Train became TTX in the early part of your target era. The JR well cars are also perfect for you and will be pretty much brand new in your era. I don't really know the appropriate container lengths for the era and when double stacks became common, but maybe someone else can fill you in.
