when i'm planning xc flight, should I use terminal chart (if its available) as my main navigation, and then sectional, after I reached the boundaries of terminal chart?

My first xc flight (with cfi) is on sunday, and my cfi asked me to plan route from RNT to HQM through VFR Seatac corridor. I made a part of the route on terminal seattle chart, and as soon as I reached SHN - i'm thinking about switching to sectional.

Is it something that should be practiced, or will get me lost?? Should i do everything just on one chart?

thanks