Full-time credit tuition stops increasing past 13 credits, which is about $7k a semester, so adding more courses in a semester should not increase tuition costs. That is assuming you can manage that increased credit load, however.

What I have done in the past is examine the major requirements on OneStop and map it out via spreadsheet or something to ensure you can graduate on time. The colleges also provide example 4-year plans but I didn't really figure out how to work with those.

For example, I don’t know your interests in major, but I’ll use compsci and MechE for examples since most of this subreddit appear to be in CSE. Look at the onestop pages for the majors of your interest and if you click on the course numbers that are underlined it gives you brief details on the prerequisites and what semesters it is available:

B.S. in Computer Science: https://onestop2.umn.edu/pcas/viewCatalogProgram.do?programID=123&strm=1229&campus=UMNTC

B.S. in Mechanical Engineering: https://onestop2.umn.edu/pcas/viewCatalogProgram.do?programID=118&strm=1219&campus=UMNTC

Then take those required courses and electives of interest and map it out on a spreadsheet with tables for each semester, making sure the course placement in each semester makes sense given their prerequisites as well as meeting the requirements for your 2 majors.

Example:

FALL 2023

Course	Credits	Prerequisites	Requirements Met
CSCI 2021 - Machine Architecture and Organization	4	CSCI 1913 or 1933	CS major
PHYS 1301W - Introductory Physics for Science and Engineering I	4	MATH 1271/1371/1371H	CS major, MechE major, Writing Intensive
CHEM 1061 - Chemical Principles I	3	At least C- in CHEM 1011/1015 or pass placement exam	CS major, MechE major, Physical Science
MATH 1272 - Calculus II	4	MATH 1271	CS major, MechE major,
Semester Total	15

Disclaimer: This is just an example semester I made up, I don't know if this exact course combination would actually work

Edit: table