Performing the Sunnah and waajib Salaah when one is a musaafir

I work in a hospital, Peterborough, UK as a medical consultant physician which 58 miles away from my house, Nottingham. I stay in hospital accommodation for 5 nights and I return to Nottingham for 2 night. Whilst in Peterborough I do attend the salah in jamaat in the local masjid, Peterborough for Fajr, Asr, Magrib and Isha.

1. With regards to sunaah and wajib do I have to do full as a mukim?

Besides, during zohr prayer I cannot go to the masjid but I do salah al Qasr if other people are not around in the hospital prayer room. I recently come across a hadith in Arba'een of Imam Nawawi RA that if a person is punctual with four sunnats of zuhr and two thereafter, Allaah will make hell forbidden for him. I just feel that I am missing this great blessing if I do salah al Qasr during zohr time.

2. In light the above, can I perform four sunnats of zuhr and two thereafter, in order to derive the above benefit? Mufti Sahib I would appreciate if you could give a comprehensive fatwaa.