The best source for what you want would probably be a Mexican-American War (MAW) equivalent for the American Civil War Official Records of the War of the Rebellion (the OR), but so far as I know no such book or series was ever prepared for the land actions in the MAW. There are several ongoing projects like the OR for early American naval actions for the American War of Independence, the Quasi-War with France, the War with the Barbery Pirates, the War of 1812, and, of course, the naval OR for the War of the Rebellion-albeit the ones I've seen as recent projects only contain a representative sample of the documents from the wars and are not a compilation of all surviving documents. The Navy does seem to have a project for the naval portion of the MAW but as that was not what you were asking for I didn't look into the project any further.
Anyway, although there does not appear to be an OR for the MAW, there are lots of government and related web sites with information and records for the war you can find with a bit of searching. I'd start with the Command and General Staff College site. It has lots of papers, articles and the like available on most American wars and there may be something there of use to you. The CGSC also has the George Nafsinger collection of OBs for all sorts of wars, including some of the actions of the MAW.
West Point's web site has its various atlases available (albeit I didn't see one on the MAW, just one onAmerican wars generally), and may also have some info on the MAW. Staff Rides and the like are also available for the American Civil War and the AWI-I think through the CGSC site (the gov and military keep reorganizing and reconfiguring its record sites and many of my bookmarks are a bit out of date), albeit I doubt there are any "Staff Rides" for the MAW, but similar stuff is likely available.
Anyway, there's lots and lots of info out there, you just need to do a bit of poking around on the internet to find it. For example, I have a pdf copy of a book/pamphlet titled "Guns Along the Rio Grande, Palo Alto and Resaca de la Palma" that's part of a series on the US Army Campaigns of the Mexican War. I found the web site I downloaded the book/pamphlet from, but now when I try to get it or the others in the series I get "404"s. I'll try to find an alternate source and post it here if I do.
Apparently the books/pamphlets in the series are available from Amazon here:
link
For about $15 USD, but I'm not sure if they are what you want.
As an alternative, Patrick Wilson, the Virtual Armchair General, was, IIRC, at one point involved in a project to provide war-games rules, figures and background research on the MAW including some books he's published. Patrick's both a great guy and an excellent researcher, and you could do worse than firing off an email to him c/o his web site for suggestions.
