Advice regarding Vampire career needed, please

Sounds fun! I never played neither vamps or detectives to the max levels, but from what I did play I only had indoor investigations. My detectives never spent much time on walking the streets, but if so I assume your vamp can take breaks as needed. Some of my vamps do use their umbrella to protect from sunlight, and if not very sunny the daylight is not immediately dangerous. I think your vamp will be fine, and there might be ways to adjust to the situation :)