Installing a transmitter that has remote diaphragm seals is an easy alternative solution to using impulse piping. They are available in a variety of process connection sizes and styles, and are commonly used in applications similar to what is described in this post (high temperature, viscous). http://www2.emersonprocess.com/en-US/brands/rosemount/Level/Differential-Pressure-Level/1199-Remote-Seals/Pages/index.aspx
Another solution is to use a Rosemount 3051S transmitter with Advanced Diagnostics. This transmitter has the unique capability to detect the presence of plugged impulse lines using Statistical Process Monitoring technology. http://www2.emersonprocess.com/en-US/brands/rosemount/Pressure/Pressure-Transmitters/3051S-Advanced-Diagnostics/spm/Pages/index.aspx