However, when wiring, she needs to be absolutely sure the routing number is correct. There's a nominal fee involved, but is worth the piece of mind and convenience. Also, CU might not accept it depending on their policies.

Mailing in a check may work, but risk of loss. Many banks and CUs limit mobile deposit to $5K or so per day. after all, how many times a week do you need to move 100K+ between banks with limited options like this? These fees and limits on bank transfers are fairly normal, its just that people dont run into them that often. only down side is there is just about always a fee to send it and often a fee to recieve the wire on the other end as well.

No real limits on a wire, typically arrives same day and is pretty safe. not even 2 months, depending on if the bank goes on calander days or a rolling 30 days, this can be done in just over 2 weeks or done in about 31 days.

Wells fargo allows 30K a month it sounds like, online CU likely allows between 25K and 50K a month themselves (rough estimates on lower and upper bounds) so she could transfer about 55K-75K per month and have it done in 2 months without an issue. however you can typically do the transfer from both ends, meaning she can link wells fargo to the online CU but she can also link the online CU to wells fargo. Bank to bank transfers (ACH transfers) typically take 2-3 days to go through and having limits on them is fairly normal.

Wells fargo online transfers