Hey there,
I think for us to give you any good suggestions we need to know some of your repertoire. Also, if this is going to be your first ever orchestral piece i advise you not to start with Liszt or Rach. Playing with an orchestra is a very different thing than playing solo and it takes much experience to play well with an orchestra. Now if it isn't your first orchestral playing then the easier of the two is Totentanz (which for most people fits quite well into the hand, if there is the technique to support it). Rhapsody on a theme of P is imo much harder musically and technically in a few variations.
If it is your first time playing with orchestra, I suggest starting with maybe Mozart concerto g major (1st movement) or Mendelssohn 1 g minor (any of the movements, one and three are quite exciting, while the 2nd is very lyrical and beautiful).
good luck