An "other" document from 1970 (Barcode 101277386) appears to be large collection of status maps for the interstate system:
* Page 276/314 has I-20 going into downtown Dallas over today's US 80, but appears it may have multiplexed with I-35E south to the current bypass alignment.
* Page 278/314: I can't tell for sure, but it appears I-20 did a similar thing for Fort Worth with a multiplex with I-35W south of downtown to run west on what is today I-30. There also appears to be faint lines for cancelled/other freeways: A north-south route west of but generally parallel to I-35W; an east-west route north of today's I-30 and south of TX 199; an east-west route farther south than today's I-30 east of downtown; and what evolved into the Chrisholm Trail Parkway.
* Page 288/314 has a nice map showing when I-415 was the southeast portion of the partial beltway for Salt Lake City.
* Page 293/314 has a map showing a redo of the interstate system around Richmond and Petersburg, VA. It's missing numbers of some of the corridors, but does show a southern bypass of Petersburg connecting I-85 to what is today I-295. It also appears I-295 would have crossed I-95 closer to today's cloverleaf with Wagner Road.
* Page 308/314 shows I-57 in Wisconsin with an "original location closer to what is today's WI 172 around Green Bay.
Some more interesting finds:
* Page 120 shows I-69 ending at I-70 a few miles east of I-465 and I-465 not existing at all between its northern I-65 junction and I-865
* Page 129 has I-80 hitting I-35 around the present-day Grand Ave exit and not at the western end of I-235
* Page 133 shows I-471 as a very short loop running on the south side of the Ohio River from I-71/75 before crossing the Ohio near its current crossing
* Page 158 shows I-696 running along (or on top of) 8 Mile Rd and I-275 running along Telegraph Rd
* Montana included street maps of all of their major cities that an Interstate was planned to pass by (even if said Interstate was never planned to enter the city limits (pages 170 to 178)
* Page 203 shows I-40 hitting I-95 in the Selma/Smithfield area and ending there (instead of crossing I-95 near Benson on its way to Wilmington)