A few things about getting into vascular access that may help you or you can do to help yourself out.
1) Most VAT are looking for critical care experience. You will be placing lines on a variety of patients of varying acuity. Most VAT that I have had experience with don't tend to bring on med-surg nurses or out of hospital practice nurses. They tend to draw from a pool of experienced VAT, ICU, or ER nurses. On rare occasion I have seen a very extensively respected and experienced tele nurse be selected. VAT is more than just the skill of using a sono and needle, it requires a lot of medical knowledge, experience, and critical thinking ability to perform safely and effectively.
2) The skills. Obviously you should make certain that your freehand IV skills are top notch, this will help you by being one less thing to learn or be concerned about when you start incorporating the ultrasound. Being that you are in hospice care right now it would likely be difficult for you to regularly get your hands on an ultrasound and vascular training phantom to start learning more about ultrasound guided VAD placement. Finding an instructor led hands on training course is about impossible in most areas. But would be of most benefit to you so that you start off with as much information and guidance as possible to speed your learning and help you avoid learning incorrect techniques, information, and habits. I offer one of these training courses, but it is only available in Texas. Also the nurses that I train tend to be from ER and ICU where an ultrasound is readily available on a daily basis and IV start needs each shift are plentiful for practice. It doesn't do much good to learn something if you wont have the opportunity to use it regularly enough to become proficient.
3) I would say network a bit. There are VAT at most hospitals. Talk to the VAT nurses at these facilities. Also talk to the ER nurses and find out who their staff is for sono IVs. There is always at least one person who taught themselves how to do it. Just be cautious since they likely taught themselves using the internet as a resource, so their techniques and knowledge may not be as accurate as it should be. Those facilities that don't have their own VAT likely contract with an outside agency that provides the service. An outside agency is another option, as most will train you for sono guided VAD placement. They do typically only hire critical care nurses, and often only want experienced VAT nurses since they travel from facility to facility with no "backup" in case of issues, and are strictly profit based operations. They tend to want people who can be up and running quickly to maximize company profits.
Don't get discouraged. If you want it you just have to do whatever it takes to get it. I can tell you that VAT RN is by far the best of all RN positions in my experience. Typically pays better, has better hours, cleaner, safer, well respected as a specialty in facility, and you do none of the things that we all hate doing as a nurse. I started in ER, have done cath lab/IR as well. I have tried to go back a couple times just to not lose my skills. But every time I go back I cant believe how much harder I have to work and usually for less money!!!
Good luck to you. Feel free to message if you have any other questions.