I feel it is time to upgrade my 1977 system.......

I have been enjoying my Pioneer Spec 1 and Pioneer Spec 2 system for a very long time and I have been having issues that have exhausted my patience and nearest shop is 3 hours (each way) from home.  I only listen to my Music Hall TT that pleases me.  My speakers are from 1976 Altec Lansing Model 19 that have been freshend up and I love the sound, I guess because I have been so accustomed to them and I'm sure there are many diff speaker options but for now I wish to continue with the Altec's.  My quest is to replace my amp and preamp.........I have some logistical problems to deal with.  I have ONE!!!! location for new gear, a shelf that is 51 inchs long and 18 inches from a wall to the front edge of the shelf, shelf will handle 200lbs.  My Pioneer amp has ample power and I would like to remain close to the same amout of power.  If you have some ideas for me I would love to hear them.  Not sure how I feel about tube gear since I have no background at all so I (think) I'd rather not go that route, but feel free to change my mind.  Budget not to exceed 18k including cables.  I know there is a wealth of knowledge here unfortunately I have very little to offer so I thank you greatly in advance......