Are there any restrictions on crossing into TJ?  How long is the time to get in and back thru ?  Thanks for any info

You are suppose to cross for "essential services". The Mexican immigration officials do not usually ask about this, but many people manufacture a story in case.  A good story is I have a early dentist appointment tomorrow and wanted to cross today and stay in a hotel so I won't be late tomorrow.  They may ask you to buy a 180 day permit which is around $30 US or just under 600 pesos.