Mr Tuffy can help....also correct tire pressure (I think 45 on an original schwinn hollywood S7 rim/tire, it should be on the side of the tire), a good rim strip and like ny biker writes also carefully look for anything embedded after a flat. When putting any liner in remember to not have it overlap at the stem. Put the middle of the liner over the stem so any overlap is opposite it. For tires ...an original hollywood S7 rim has a wider bead seat diameter than a regular 26 1.75 tire. Kenda use to make a correct sized tires for all the S7 and other schwinn rims and still should.

Enjoy learning more about maintenance…it’s one of those things that can help in feeling more positive self-confidence in riding....and congrats on the longer rides!!!!!! keep going girl