Wow, looks like some of you guys are already packing.
I will try to keep this updated and answer questions regularly.
The mission analysis is normally the key, but in this case, it isn't the destination, but the journey. Do not overly focus on the recording of the journey beyond what was given above. Focus on the tools and skills you will need to get there.
The Time Travel Commission has not been invented yet. Once you clear initial white man country, pretty much any gear you have is GTG to use. If you are worried, wear an overcoat and put some skins over your ruck. There is no external moral component here either, you can do as you wish in your interactions. At the same time, you might think about what happened in Salem, Mass only eight years previously.
I see some people going extremely light, and some extremely heavy. Anyone planning on humping a laminated stack of 1:24,000s of the entire US needs to do a quick count and check the shipping weight. Those who plan to do it in their skivvies with a Kabar in their teeth need to step outside like that and spend a night on the ground.
I think the 18-24 month time estimate is correct, which means two winters. Those with a northern route may want to consider that. Do you plan on holing up for the winter, maybe building a semi-permanent shelter, or pressing on regardless? Pretty hard to travel and gather food in the winter while crossing the Great Lakes and Northern Plains on foot. Hostile natives are a legitimate concern, as they were for our forefathers. Good research might ID a route through friendlier country.
Starting in the spring with plans to cross in 300 days is unrealistic, but you are welcome to try it. Remember that you have to catch, kill, and prepare your food daily. Crossing two major mountain ranges, some huge rivers, and a desert or two, all on foot, might slow you down. Also consider that your schedule would put you in a Donner Pass situation, where you will be in the Rockies/Sierra Nevadas in January/February. You will probably not make 10 miles per day then, if you can move at all.
Some of the natives will definitely be hostile, but 5.56 will not be particularly effective on a bear or a moose. This is not strictly a combat patrol, though there will almost certainly be some.
Shotgun shells are notoriously poor tradeoffs in weight for game gathered. Let me know what 300 rounds of 20 gauge shot weighs.
If I have to live outside for two years, 'skeeters, rain, snow, etc., I am inclined toward the tent crowd, or at least a shelter of some sort. Winters will require a sleeping bag or equivalent skins (heavier).
Anyone wishing to present an opposing viewpoint, feel free to do so. I am not an expert at this, just trying to look at some alternatives to exercise my mind and reconsider some of my kit.
Thanks to all who have contributed.
TR