Is it permissible for someone performing Umrah who comes by land from Qatar to rest in Ta'if and then enter into a state of Ihram from As-Sail Al-Kabeer?

There is no objection for someone whose Miqat is As-Sail Al-Kabeer to rest in Ta'if and prepare for Ihram, then enter into Ihram for Umrah and make the Talbiyah before passing the Miqat. The important thing is not to pass the Miqat intending to perform the rituals while not in a state of Ihram, based on the saying of Ibn Abbas (may Allah be pleased with them both): "These are for them and for whoever comes upon them from other than their people, among those who intend Hajj and Umrah." It is recommended to enter into Ihram immediately after prayer; if a prescribed prayer is due, one should enter Ihram after it, otherwise, one should pray two rak'ahs as a voluntary prayer and then enter Ihram.