Long Weekend
by Kegler

Ten answers become different words before entry; the unclued center entry explains how to modify them.

Long Weekend grid

Across
1Diagram describing his bad accident
7Accent small hair sample
11Cain's son brought back piece of his ice cream container
12Signs of elected officials keeping track, finally
13Carrying on parade for leader
14Both sides embracing one recluse
15Light and furry, not hot
17Hooligan jailbird conceals Mary Jane
18Easily crushed myth surrounding Rhode Island
19Injured ewe beginning to plaintively cry
20Rich doctor acquires one pair of yearlings
22Mildly deranged group returning to club
26Certain keyboardist's bizarre ruse
28Lucy's mate gripped by altitude sickness
29See instructions
31Start to overcorrect and turn right in curve
33Sell victuals, at first, then stop
36Cloisters' cooks adopting excited air
38One learning from fall of Troy
40Submit chapter depicting desire
42Bringing back guns for deer
43Elliptical space behind band
45Issue of “Time” sent back
46Reportedly seals up lakes
47Spirit of Twisty Lane
48Run away from insect, we hear
49Fearsome at first, more dangerous and more lively
50Poke holes in puzzle
51Members of joints playing nonets
Down
1Destroy germ with last of antidote blend
2Things that are embedded in songs
3Orbiter circling back of sun; thus, strong wind
4Leading one had written about episode's finale
5Ramble around one Raider
6Complete transformation of venue, a bit drab
7Adept seamstress finally stopped
8Every other greasy spoke
9Seer misinterpreted Celtic language
10Boost crazy pol wearing dress
16Fiddles with thousand in funds
21Glacial ridge reeks badly
23Ring operated in Algerian port
24Blossom like a worker?
25Better amortize, mister
27Eye sore sounds like an eyesore
30It's back in tunnel with enemy
32Destiny involving truck and ship
34Legate's funny bald baby?
35A siren scrambled out of bed
37Stooge captures confused goons with ferret-like mammal
39Fragrances from cedarwood or sandalwood
41Roue hugs lass, initially wearing clothes
44River circles around Hawaii
45Cruel person entertaining rare pal

Solution