I have had to travel large distances for medical procedures. What mileage and meals are allowances are there and where do I claim them?

This CRA page has info on what you can claim: https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/rc4065/medical-expenses.html#toc14

In TurboTax you would enter your travel & meal expenses in the Medical Expenses section as "other".