Don't undercharge because you work remotely. In serious business it may be perceived as lower quality work.

For long term contracts it is better to stick to constant daily rate, whatever you are on site or remote, as this makes companies planing and accounting easier. Of course it is fine to charge for travel expenses but that should be also agreed upfront.

Depending on work arrangement your costs may be even higher with remote gig - work space, utility bills, software licenses, hardware, occasional travelling, accountant etc.

I think a lot of companies would choose the 50% higher salary if given that choice.